Eng-ir.  ( 


Published  under  Supervision  of 

A.  Eugene  Michel  and  Staff, 
Advertising  Engineers,  New  York, 

and  printed  by 
Franklin  Printing  Co.,  Philadelphia 


STEAM  HEATING 


A  Manual  of  Practical  Data 

Compiled  by 
THE  GENERAL  ENGINEERING  COMMITTEE 

OK 

WARREN  WEBSTER  &  COMPANY 


PUBLISHED  BY 

WARREN  WERSTER  &  COMPANY 

CAMDEN,  N.  J. 


First  Edition,  Revised.     May,  1922 
Copyrighted  1922  by  Warren  Webster  &  Company 


Price  $3.25  Net 


/O    v    I 

u1  \/^ir~. 

X-£-<7 


Engineering 
Library 


FOREWORD 

r  1 1HE  subject  of  Heating  and  Ventilation  has  been  covered  broadly  in 
many  handbooks  that  are  available  for  reference,  but  there  has  been 
a  demand  also  for  a  book  of  information  confined  exclusively  to  Steam 

Heating  and  covering  that  field  in  all  necessary  detail. 

Steam  Heating  is  therefore  the  one  topic  of  this  volume  and  the  editors 
have  aimed  to  cover  the  subject  with  comprehensive  data,  arranged  in  such 
convenient  and  useful  form  as  will  best  meet  the  needs  of  technical  men  in 
the  engineering  and  contracting  fields. 

The  information  given  is  authentic,  being  based  upon  actual  practice 
and  largely  upon  the  experience  of  Warren  Webster  &  Company,  who,  as 
pioneers,  have  specialized  for  more  than  thirty  years  in  the  effective  use  of 
steam  for  all  heating  purposes.  Many  of  the  designs  and  methods  originated 
by  this  firm  are  now  the  recognized  service  standards. 

Special  articles  and  helpful  suggestions  have  been  contributed  by  John 
A.  Serrell,  by  the  General  Engineering  Committee,  and  by  John  B.  Dobson, 
Ralph  T.  Coe,  William  Roebuck,  Russell  G.  Brown,  Harry  E.  Gerrish, 
Howard  H.  Fielding,  George  A.  Eagan,  E.  K.  Lanning  and  other  members 
of  the  Webster  organization. 

"Steam  Heating"  offers  the  best  thought  of  this  organization,  and  as 
part  of  Webster  Service,  it  is  intended  to  be  of  real  value  throughout  the  pro- 
fession. The  observance  of  good  judgment  and  painstaking  care  in  following 
its  teachings  will  do  much  toward  obtaining  creditable  and  satisfactory 
results. 

If  further  explanations,  additional  information  or  helpful  co-operation 
are  desired,  the  Engineers  and  Service  Men  in  the  branch  offices  of  Warren 
Webster  &  Company  throughout  the  country  are  always  available  for 
consultation  and  assistance. 

CAMDEN,   NEW   JERSEY  WARREN  WEBSTER  &  COMPANY 

JANUARY    1,  1922 


GENERAL  ENGINEERING  COMMITTEE 


OF 


WARREN  WEBSTER  &  COMPANY 

William  M.  Treadwell,  Chairman 
John  A.  Serrell,  Advisory  Engineer 

William  F.  Bilyeu        J.  Logan  Fitts  Harry  M.  Miller 

Charles  F.  Eveleth      Sidney  E.  Fenstermacher        Rudolph  G.  Rosenbach 


CONTENTS 

PART  I.— STEAM  HEATING 

PAGE 

Chapter  I. — Elements  of  Steam  Heating 9 

Chapter  II. — Data  Required  for  Steam  Heating 

System  Design 15 

Topography 15 

Location  and  character  of  source  of  heat •' 15 

Exposure  and  protective  conditions 

Outside  temperatures 

Floor  plans,  elevations  and  cross-sections 

Inside  temperature  requirements 

Contents  and  use  of  enclosure 

Character  and  location  of  heating  surface 19 

Location  of  supply  and  return  lines 20 

Chapter  III. — Heat  Transmission 

Chapter  IV. — Air  Infiltration 31 

Chapter  V. — Method  of  Calculating  Heat  Requirements 34 

Chapter  VI. — Method  of  Computing  and  Selecting  Heating  Surface.  .  .  42 
Chapter  VII. — Ventilation  Problems  as  They  Affect  the  Design  of  Heat- 
ing Systems 59 

The  fireplace 60 

Direct-indirect  system  of  heating  and  ventilation 60 

Indirect  system  of  gravity  ventilation 60 

School  buildings 61 

Theatres  and  auditoriums;  churches 63 

Banquet  halls,  dining  rooms,  meeting  halls,  etc 64 

Exhaust  ventilation  of  industrial  plants 65 

Hot  blast  systems  of  heating  for  industrial  plants 66 

Factors  entering  design  of  complete  heating  and  ventilating  plant 67 

Air  quantities  required  for  ventilation. 67 

Sizing  of  the  ducts 68 

Calculation  of  resistance  or  pressure 

Selecting  the  apparatus 

Size  and  arrangement  of  fans;  heaters 72 

Boiler  horsepower  required 73 

Chapter  VIII. — Proportioning  of  Chimneys 

Chimneys  for  house-heating  boilers 

Chimneys  and  draft  for  power  boilers 78 

Draft 

Draft  formula • 79 

Draft  losses  and  loss  in  stack 80 

Height  and  diameter  of  stacks 

Losses  in  flues 83 

Loss  in  boilers  and  in  the  furnace 84 

Draft  required  for  different  fuels 

Rate  of  combustion 85 

Solution  of  a  problem 86 

Correction  in  stack  sizes  for  altitudes 87 

5 


Chapter  IX.— Boilers 89 

Chapter  X. — Selection  of  the  Proper  Type  of  Steam  Heating  System . .  95 

Size  and  type  of  building ." 97 

Residences 97 

Apartment  buildings 97 

Store  and  office  buildings 97 

Public  buildings 98 

Use  of  building 100 

Location  of  building  and  topography  of  site 101 

Construction  and  architectural  features 103 

Sources  of  steam  supply 103 

Operation  and  attention 107 

Chapter  XI. — Flow  of  Low-pressure  Steam  Through  Piping 110 

Flow  of  steam  through  pipes 110 

Friction  in  run Ill 

Condensation  loss 113 

Effect  of  deflection,  contraction  and  expansion 113 

Pressure  drop 114 

Modulation  systems 116 

Vacuum  systems 120 

Sizing  of  piping 123 

Vacuum  system 123 

Condensation  allowances 124 

Pressure  drop  for  initial  velocity 125 

Modulation  system 127 

Chapter  XII. — Critical  Velocities  in  Radiator  Run-Outs 132 

Chapter  XIII. — Vacuum  Pumps  and  Auxiliary  Equipment 137 

Proportioning  of  steam  end  of  reciprocating  vacuum  pump 143 

Power-driven  reciprocating  vacuum  pumps 143 

Disposal  of  vacuum  pump  discharge 144 

To  waste 144 

To  air-separating  tanks 144 

To  open  vent  tanks 145 

To  hydro-pneumatic  tanks 147 

To  loop  seal  on  tank  outlet  to  heater  or  boiler 148 

To  receiver  and  boiler-feed  or  tank  pump 148 

Dry-vacuum  pump  receiver  and  water  pump 150 

Suction  strainers. 151 

Vacuum  governors 151 

Chapter  XIV. — Laboratory  Tests  of  Return  Traps 153 

Tests  for  heating  efficiency 154 

PART  II.— WEBSTER  SYSTEM  SPECIALTIES  AND  APPLICATIONS 

Chapter  XV. — Webster  Systems  of  Steam  Heating 161 

Webster  Modulation  Systems 161 

Boilers  operating  up  to  10-lb.  pressure 162 

Boiler  pressure  from  10-to  50-lb 163 

Street  system  carrying  any  pressure 164 

6 


Chapter  XV. — Continued 

Webster  Vacuum  Systems 165 

With  power  boilers 165 

Dripping  supply  mains  and  risers 167 

Radiator  connections 169 

Disposal  of  the  products  of  condensation 170 

The  vacuum  pump 170 

Final  disposal  of  the  condensation 171 

Ventilation  problems 172 

With  medium-pressure  boilers 172 

With  low-pressure  boilers 173 

Steam  furnished  from  street  system 173 

Special  modifications 173 

Webster  Conserving  System 173 

Webster  Hylo  Vacuum  System 176 

Chapter  XVI. — Applications  of  the  Webster  System  to  Lumber  and 

Other  Kiln-Drying  Problems 179 

Chapter  XVII. — Applications  of  the  Webster  System  to  Slashers  and 

to  Cloth  and  Paper  Drying  Apparatus 188 

Cloth  and  warp  drying  machines 190 

Paper  machines 192 

Chapter  XVIII. — Applications  of  the  Webster  System  to  Railroad 

Terminals  and  Steamship  Piers 194 

Chapter  XIX. — Applications  of  the  Webster  System  to  Vacuum  Pans 

and  Similar  Apparatus 196 

Chapter  XX. — Applications   of   the   Webster   System   to   Sterilizers, 

Cooking  Kettles  and  Similar  Apparatus 202 

Hospital  equipment 202 

Cooking  kettles,  plate  warmers,  bain-maries,  coffee  urns  and  other  kitchen 

equipment 204 

Chapter  XXI. — Applications  of  the  Webster  System  to  Greenhouses.  .  205 

Chapter  XXII.— Installation  Details 215 

For  Webster  Vacuum  System  and  Webster  Modulation  System 215 

For  Webster  Vacuum  System  only 222 

For  Webster  Modulation  System  only 228 

Chapter  XXIII. — Capacities  and  Ratings  of  Webster  Valves  and  Traps  233 

Modulation  Supply  Valves 234 

Return  Traps 237 

Selection  of  Modulation  Supply  Valves  and  Return  Traps 238 

Heavy-duty  Return  Traps 239 

Series  20  Modulation  Vent  Traps 239 

Modulation  Vent  Valves 240 

Chapter  XXIV. — Appliances  for  Webster  Systems  of  Steam  Heating  211 

Return  traps 241 

Sylphon  Trap 242 

No.  7  Trap 246 

7 


Chapter  XXIV.— Continued 

Heavy-duty  Trap,  standard  and  high-differential  types 247 

Type  W  Modulation  Valve 250 

Double-service  Valve 252 

Oil  Separators 254 

Low-pressure  Receiver  Oil  Separators 257 

Grease  and  Oil  Traps 257 

Suction  Strainer 258 

Dirt  Strainers 259 

Vacuum-pump  Governor 260 

Suction  Strainer  and  Vapor  Economizer 261 

Lift  Fittings,  Series  20 263 

Receiving  Tanks 264 

Water  Accumulator 267 

Gauges  for  Webster  Systems 267 

Modulation  Vent  Trap 268 

Modulation  Vent  Valve 270 

Damper  Regulator 271 

Hylo  Vacuum-control  Sets 272 

Sylphon  Conserving  Valve 273 

Low-pressure  Roiler  Feeder,  Series  16 274 

High-pressure  Sylphon  Trap 275 

Hydro-pneumatic  Tanks 276 

Expansion  Joints 278 

Steam  Separators,  Series  21 283 

Chapter  XXV. — Specifications  for  Webster  Systems 286 

Vacuum  System 286 

Modulation  System 289 

Chapter  XXVI.— Webster  Sylphon  Trap  Attachments 293 

For  Sylphonizing  Webster  Traps  of  earlier  types 293 

No.  422  Webster  Thermostatic  Valves 294 

Webster  Motor  Valves 294 

No.  422  Webster  Water-seal  Motors 294 

No.  522  Water-seal  Traps 295 

Multiple-unit  Webster  Valves  of  earlier  types 296 

For  Sylphonizing  radiator  outlet  valves  of  other  makes 297 

Chapter  XXVII. — Fuel  Saving  by  Preheating  Boiler-feed  Water ......  301 

Webster  Feed-water  Heaters 302 

Standard  Type 304 

Preference  Cut-out  Heater 308 

The  Webster-Lea  Heater  Meter 313 

PART  III.— ADDENDA 

Chapter  XXVIII. — Miscellaneous  Useful  Information 315 

For  lists  of  illustrations  and  tables,  and  detailed  index,  see  back  of  book  (Page  354) . 


NOTE. — For  convenient  reference,  each  table,  illustration  and  formula 
is  given  a  compound  number,  the  first  part  of  which  indicates  the  chapter 
and  the  second  the  sequence  in  that  chapter.  Example:  Table  3-6  indi- 
cates the  sixth  table  in  Chapter  3. 


Part  I— Steam  Heating 

CHAPTER  I 

Elements  of  Steam  Heating 

THE  purpose  of  a  heating  system  is  to  warm  the  interior  of  a  structure 
to  a  desired  degree  of  temperature  and  to  maintain  this  condition 

against  a  lower  exterior  degree.  It  is  usual  to  assume  the  exterior 
temperature  to  be  the  average  minimum  expected  in  the  locality. 

To  warm  the  interior  and  to  maintain  a  given  temperature,  heat  is 
required  to  replace  that  which  is  absorbed  by  the  contents  and  that  trans- 
mitted through  the  structure  to  the  exterior. 

The  unit  measure  of  heat  in  English-speaking  countries  is  the  British 
thermal  unit,  which  is  the  heat  necessary  to  raise  the  temperature  of  one 
pound  of  water  from  59  to  60  deg.  fahr.  This  is  commonly  known  as  B.t.u., 
or  heat  unit. 

The  quantity  of  heat  required  to  raise  the  temperature  of  a  given 
weight  of  a  substance  through  one  deg.  fahr.  as  compared  with  the  quantity 
of  heat  required  to  raise  the  same  weight  of  water  from  62  deg.  to  63  deg. 
fahr.  is  called  the  specific  heat  of  that  substance. 

The  heat  content,  or  quantity  of  heat  per  degree  of  a  given  mass  of  a 
substance,  is  the  product  of  its  specific  heat  and  its  weight  in  pounds. 

The  rate  at  which  initial  heat  is  required  to  raise  the  temperature  of  a 
cold  structure  and  its  contents  to  the  desired  degree  in  a  given  time  may 
be  much  greater  than  that  necessary  to  maintain  the  required  temperature 
after  initial  heating,  or  warming  up,  has  been  accomplished. 

The  greater  the  length  of  time  permitted  for  initial  warming,  the  less 
difference  there  will  be  between  the  heat  requirement  per  unit  of  time  during 
initial  heating  and  that  required  during  subsequent  maintenance. 

Heat  losses  by  transmission  through  various  forms  of  building  structure 
have  been  ascertained  with  more  or  less  accuracy,  and  much  information  on 
this  subject  has  been  published  from  time  to  time.  These  data  are  being 
constantly  improved  as  new  forms  of  construction  appear. 

The  principal  discrepancies  between  published  data  on  transmission  are 
probably  due  mainly  to  various  allowances  which  have  been  included  for 
infiltration.  Infiltration,  or  air  leakage,  should  be  considered  independently 
of  structural  transmission. 

•  Local  differences  in  workmanship  and  material  of  structure,  as  well  as 
errors  in  observation,  have  further  contributed  to  discrepancies,  and  in 
many  instances  the  results  of  tests  observed  at  one  temperature  difference 
have  been  reduced  by  direct  proportion  to  a  "  per-degree-difference "  basis. 

Until  recently  it  has  not  been  generally  recognized  that  this  last-men- 
tioned basis  is  in  error,  in  that  it  is  likely  to  give  too  high  a  rate  of  heat  loss 
for  smaller  temperature  difference  and  too  low  a  rate  for  larger  temperature 
difference  than  that  existing  during  the  test. 


The  heat  transmission  factors  in  Chapter  3  are  based  upon  experience 
with  various  substances  used  in  construction  under  average  conditions  at  a 
difference  of  70  deg.  fahr.  between  interior  and  exterior  temperatures. 
Factors  for  other  temperature  differences  are  stated  as  percentages  of  the  70 
deg.  normal.  The  effects  of  exposure  and  of  varying  wind  velocities  are 
separately  considered  as  losses  due  to  infiltration. 

In  order  to  determine  the  amount  of  heat  required  it  is  necessary  to 
know  or  establish: 

First:  The  lowest  temperature  to  which  the  interior  will  fall,  that  is, 
the  "initial"  temperature;  and  the  temperature  which  it  is  desired  shall  be 
maintained  within  the  enclosure,  or  the  "maintained"  temperature; 

Second:  The  time  period  in  which  it  is  required  that  the  structure  and 
jts  contents  must  be  raised  from  initial  to  maintained  temperature; 

Third:  The  nature  and  the  weight  of  the  building  and  its  contents 
(especially  if  large  quantities  of  glass,  metal  or  water  are  included) ; 

Fourth:  The  minimum  exterior  temperature; 

Fifth:  The  direction  and  anticipated  velocities  of  prevailing  cold  winds; 

Sixth:  The  construction  of  the  enclosure ; 

Seventh:  The  topography  of  the  site,  and  other  local  peculiarities. 

The  heat  transmitted  hourly  through  the  structure  at  a  temperature 
difference  between  maintained  interior  and  minimum  exterior  temperatures, 
plus  the  heat  required  to  warm  the  infiltrated  air  through  the  same  difference 
of  temperature,  gives  the  hourly  maximum  heat  requirement  during  main- 
tenance. In  Chapters  3  and  4  these  two  causes  for  heat  requirements  are 
further  discussed. 

During  initial  heating  or  "warming  up,"  heat  units  in  addition  to  those 
required  for  maintenance  must  be  supplied  to  raise  the  temperature  of  the 
structure  and  its  contents  of  air  and  stored  materials  from  their  initial 
temperature  to  the  desired  temperature. 

In  practice  the  heat  absorbed  by  the  structure  and  its  stored  materials 
is  usually  neglected,  as  the  error  is  small.  However,  if  the  interior  walls  or 
columns  are  massive,  or  if  the  contents  of  the  building  include  large  quan- 
tities of  materials  with  high  specific  heats,  such  as  iron,  steel,  water,  glass, 
etc.,  the  heat  which  is  absorbed  by  these  must  be  taken  into  account. 

In  almost  all  cases  the  heat  required  to  raise  the  air  contents  of  the 
enclosure  from  the  initial  to  the  maintained  temperature  must  be  considered. 

After  determining  the  amount  of  heat  required  to  warm  the  various 
substances  during  initial  heating,  the  hourly  rate  at  which  this  additional 
heat  must  be  supplied  during  initial  heating  is  obtained  by  multiplying  this 
heat  quantity  by  the  reciprocal  of  the  warming-up  period  in  hours. 

Applications  of  the  problem  of  determining  the  heat  requirements  will 
be  found  in  Chapter  5. 

Where  the  heating  requirements  for  warming-up  are  large  compared 
with  those  for  maintenance,  the  radiation  necessary  for  the  warming-up 
requirements  and  consequently  the  heat  emitted  will  be  correspondingly 
excessive  during  maintenance.  It  is  often  advisable  to  increase  the  length 
of  the  warming-up  period  first  allowed  in  order  to  reduce  this  excess  radiation. 

10 


Overheating  after  the  initial  warming-up  period,  may  be  avoided  by  the 
manipulation  of  the  hand-controlled  inlet  valves  on  the  radiators  or  by  a 
system  of  automatic  temperature  control. 

Having  estimated  the  total  hourly  heat  requirement,  the  next  consider- 
ation is  the  proper  proportioning  and  distribution  of  radiating  surfaces 
throughout  the  enclosure,  for  obtaining  the  desired  heating  effect  from  the 
circulation  of  a  fluid  of  higher  temperature. 

In  the  following  chapters  the  fluid  considered  for  conveying  heat  is 
steam  at  pressures  slightly  above  that  of  the  atmosphere.  The  high  thermal 
value,  or  B.t.u.,  per  pound  of  steam  and  the  convenience  with  which  it  can 
be  utilized  by  means  of  commercial  boilers,  radiating  surfaces,  pipe  and  fit- 
tings and  the  special  apparatus  of  the  Webster  Systems,  have  demonstrated 
the  superiority  of  steam  at  low  initial  pressures  for  the  great  majority  of 
installations. 

The  radiating  surfaces,  or  radiation,  normally  used  in  low-pressure 
steam  heating  to  transmit  heat  from  steam  to  the  enclosure  to  be  warmed, 
are  of  two  general  classes,  Direct  and  Indirect,  each  of  which  has  many 
specific  sub-divisions. 

Direct  radiation,  properly  classified,  comprises  only  those  arrangements 
of  radiating  surface  which  are  located  directly  in  the  space  to  be  heated. 

Radiation  which  is  not  wholly  exposed  in  the  space  to  be  heated  is 
termed  indirect  radiation.  Units  which  are  concealed  under  window  boxes, 
or  in  housings  having  an  air  inlet  near  the  floor  line  and  a  heated  air  outlet 
above  the  radiation,  or  which  are  enclosed  in  casings  outside  of  the  space 
to  be  heated  and  which  have  a  cool-air  inlet  from  any  source  and  a  warm- 
air  connection  to  convey  by  heated  air  the  necessary  heat  units  to  the 
space  to  be  heated,  are  examples  of  this  type  of  radiation. 

Originally  the  circulation  of  air  for  indirect  heating  by  the  method  last 
mentioned  was  induced  entirely  by  the  difference  in  weight  of  the  air  columns 
before  and  after  coming  into  contact  with  the  enclosed  radiating  surface. 
Present  usage  designates  such  surfaces  as  gravity  indirect,  distinguishing 
them  from  surfaces  used  in  the  later  development,  where  additional  circu- 
lating velocity  is  imparted  mechanically  by  a  fan  or  blower.  Where  mechan- 
ical means  are  used  these  surfaces  are  now  designated  as  mechanical  indirect 
or  blast  surfaces. 

Certain  forms  of  radiating  surfaces  exposed  in  a  room  and  so  arranged 
with  dampers  and  ducts  that  air  wholly  from  the  room  or  partly  from 
without  may  be  used  to  convey  heat  from  the  surface  of  the  radiator  to  the 
room,  are  called  direct-indirect  surfaces. 

The  rate  of  heat  transmission  through  radiating  surfaces  from  a  given 
interior  to  a  given  exterior  temperature  varies  not  only  with  all  classes  of 
radiation  but  with  all  sub-divisions  of  those  classes.  This  is  due  mainly  to 
variation  in  convection,  that  is,  in  the  facility  for  absorption  of  heat  from 
the  outer  surface  into  the  surrounding  medium,  and,  in  a  lesser  degree,  to  the 
dispersion  of  radiant  heat.  So  great  is  this  variation  that,  under  similar 
conditions  of  location  and  temperature  difference,  and  even  in  the  simplest 
form  of  direct  radiation,  a  low,  narrow  radiator  gives  off  40  per  cent  more 
heat  per  square  foot  of  radiation  than  one  that  is  extremely  high  and  wide. 

11 


The  term  "square  feet  of  radiation,"  therefore,  means  nothing  specific 
and  should  not  be  used  indiscriminately  for  sizing  boilers,  mains  or  other 
apparatus  in  the  heating  system. 

The  radiating  surface  for  the  local  conditions,  heat  requirements 
and  architecture,  having  been  selected  and  located,  the  proper  size  of 
radiating  units  should  be  determined.  For  this  purpose  the  information  on 
heat  emission  of  various  types  of  radiation,  Chapter  6,  will  be  found  useful. 

The  pipes  which  convey  the  heating  fluid  from  its  source  to  the  radiating 
surfaces  are  termed  supply  mains.  Those  conveying  the  products  of  con- 
densation from  the  radiating  surfaces  to  the  point  of  disposal  are  termed 
return  mains.  The  vertical  parts  of  these  mains  are  usually  called  risers, 
to  distinguish  them  from  horizontal  runs.  Risers,  in  turn,  are  classified  by 
their  direction  of  flow,  as  up-feed  or  down-feed  risers.  The  small  branches  to 
individual  units  of  radiation  are  known  as  run-outs ;  those  supplying  several 
units  as  branches,  and  those  conveying  all  of  the  heating  medium  are  usually 
termed  trunk  mains. 

The  flow  of  the  heat-carrying  medium  is  always  toward  a  lower  pressure, 
and  if  the  medium  is  steam  confined  in  pipes  or  ducts  sealed  from  the  atmos- 
phere, the  arbitrary  dividing  line  conventionally  drawn  between  pressure 
and  vacuum  does  not  enter.  The  problem  involves  only  heat  content, 
density,  difference  in  pressure,  condensation  and  friction. 

If  the  lowest  terminal  pressure  in  the  system  is  that  of  the  atmosphere 
as  in  an  open-return  line  or  modulation  system,  the  initial  pressure  must  be 
somewhat  above  that  of  the  atmosphere.  The  amount  of  pressure  above 
atmospheric  depends  largely  upon  the  friction  which  must  be  overcome 
in  the  piping  and  upon  the  pressure  necessary  to  give  the  steam  its  initial 
velocity.  If,  however,  a  terminal  pressure  lower  than  that  of  the  atmosphere 
is  mechanically  maintained,  as  in  vacuum  systems,  the  initial  pressure  may 
be  above,  at  or  below  that  of  the  atmosphere  as  best  meets  the  local 
conditions. 

Vacuum  system  practice,  with  few  exceptions,  demands  that  a  steam 
pressure  at  least  equal  to  that  of  the  atmosphere  be  maintained  in  the  run- 
outs most  distant  from  the  source  of  steam  supply,  in  order  to  avoid  the  in- 
leakage  of  air  that  would  otherwise  probably  occur  through  minute  leaks. 
This  terminal  pressure  requires  an  initial  pressure  higher  in  some  degree 
than  that  of  the  atmosphere.  Local  conditions,  such  as  source  of  supply, 
length  and  character  of  pipe  run,  and  use  and  permanency  of  the  plant, 
make  the  selection  of  pressure  difference  one  of  good  engineering  judgment 
rather  than  the  application  of  any  fixed  rule.  The  proper  basis  for  propor- 
tioning the  supply  system  is  dealt  with  in  Chapter  11. 

The  primary  function  of  return  mains  is  the  removal  and  disposal  of 
the  products  of  condensation.  These  mains  should  provide  gravity  flow 
wherever  possible.  Pressure  difference  should  be  used  to  stimulate  flow  only 
where  gravity  alone  is  not  practical. 

The  products  to  be  removed  consist  of  water,  air,  vapor,  gases  from 
impurities  and  last,  but  not  to  be  overlooked,  dirt  and  foreign  matter. 

The  last  consists  of  initial  impurities  such  as  core-sand,  gravel,  chips, 
mill  scale,  grease,  etc.,  left  in  the  heating  system  when  erected,  together 

12 


with  rust  particles  and  scale  from  impure  feed  water.  Were  it  not  for  the 
dirt  which  collects  and  the  uncertainty  as  to  its  volume,  return  mains 
ini^ht  be  made  much  smaller. 

Formulae  and  tables  of  capacities  of  straight,  smooth  pipes  laid  on  even 
grades  for  return  of  condensation,  and  tables  of  accepted  capacities  com- 
pensating for  uncertainties  of  grade  and  dirt  are  given  in  Chapter  11. 

The  hot  distilled  water  should  be  returned  to  the  boiler  wherever  pos- 
sible. The  saving  due  to  the  heat  content  of  this  water  and  its  freedom 
from  scale-forming  and  other  impurities,  warrants  considerable  initial  out- 
lay in  return  apparatus. 

No  specific  type  of  return  apparatus  will  best  fit  all  conditions.  The 
single  low-pressure  heating  boiler  may  have  its  water  line  so  located  that 
the  water  of  condensation  will  flow  back  into  the  boiler  by  gravity  against 
the  highest  steam  pressure  carried.  Between  this  simple  case  and  a  modern 
high-pressure  central  generating  plant,  where  part  of  the  exhaust  steam  is 
used  as  a  by-product  for  heating  purposes  in  an  extended  group  of  build- 
ings, there  is  a  wide  range  of  conditions.  The  selection  of  the  best  combi- 
nation of  return  apparatus  for  the  individual  plant  is  therefore  dependent 
upon  comprehensive  practical  experience. 

Some  of  the  possible  combinations  of  return  apparatus  are  described 
and  shown  in  typical  diagrams  in  Chapter  13,  and  basic  rules  are  given  for 
estimating  proper  sized  apparatus.  However,  it  is  manifest  that  discussion 
in  this  volume  cannot  cover  all  requirements,  and  in  this,  as  in  the  selection 
of  all  apparatus  for  special  conditions,  it  is  recommended  that  specific 
engineering  advice  be  obtained  from  the  home  office  or  a  nearby  branch 
of  the  manufacturer,  before  a  selection  is  made. 


13 


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14 


CHAPTER  II 

Basic  Data  Required  for  Design  of  a 
Steam  Heating  System 

INTELLIGENT  design  of  any  heating  system  in  either  new  or  existing 
buildings  requires  that  certain  basic  data  shall  be  available.     For  exist- 
ing buildings  the  present  use  of  which  will  continue,  it  is  usually  possible 
to  obtain  quite  definite  data  to  work  upon.     If  plans  are  the  available  in- 
formation, much  of  the  necessary  data  must  be  based  upon  assumptions  of 
probable  conditions. 

In  any  event,  good  judgment,  preferably  founded  upon  ripe  experience, 
must  play  its  equal  part  with  scientific  knowledge  in  the  final  application 
of  the  data  obtained. 

TOPOGRAPHY:  The  design  of  an  efficient  heating  system,  especially 
where  a  group  of  buildings  is  being  considered,  requires  that  a  careful  study 
be  made  of  the  grade  levels  of  the  different  buildings,  each  one  to  the;  other, 
so  that,  if  possible,  the  condensation  from  the  heating  surfaces  may  flow 
by  gravity  to  a  central  point  from  which  it  may  be  returned  to  the  source 
of  steam  supply. 

In  cases  where  the  conditions  are  such  that  the  condensate  will  not 
flow  by  gravity  to  a  central  point,  special  methods  for  lifting  the  con- 
densate to  a  higher  level  are  necessary  as  described  hereafter. 

LOCATION  AND  CHARACTER  OF  SOURCE  OF  HEAT:  It  follows  from  the 
above  that  wherever  possible  the  source  of  steam  supply  should  be  located 
at  a  lower  level  than  that  of  the  buildings  to  be  heated. 

In  a  plant  consisting  of  a  group  of  buildings  there  is  usually  a  power 
generating  plant,  the  by-product  from  which,  in  the  form  of  exhaust  steam, 
should  be  utilized  to  the  fullest  extent  in  the  heating  of  the  buildings.  The 
economies  incident  to  the  use  of  this  exhaust  steam  as  a  by-product 
frequently  determine  the  adoption  of  an  isolated  power  generating  plant 
rather  than  the  purchase  of  power  from  outside  sources  and  the  installation 
of  a  boiler  plant  for  heating  purposes  only. 

EXPOSURE  AND  PROTECTIVE  CONDITIONS:  By  exposure  is  meant  the 
relation  of  the  outside  surfaces  of  the  building  or  buildings  to  the  prevailing 
cold  winds  of  winter,  which  by  their  pressure  cause  infiltration  of  excess 
quantities  of  cold  air  and  the  rapid  removal  of  heat  from  the  outside  surfaces 
of  the  structure.  To  offset  this,  a  larger  amount  of  radiation  must  be 
provided  on  the  sides  having  greatest  exposure,  than  for  sides  more  favorably 
located  with  the  protection  of  surrounding  buildings  or  hills. 

Consequently  the  designer  should  determine  the  direction  of  the  pre- 
vailing winter  winds  and  their  probable  velocities  and  duration  as  well  as  the 
topographic  features  which  may  afford  protection. 

15 


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Bl  I  31  Si  I 

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i  20  25  30  4  9  14  19  24  29  3  8  13  18  23  28  5  10  15  20  25  30  4  9  14  1'9 

Fig.  2-2.     Daily  maximum  and  minimum  temperatures  in  New   York  City   during   the  heating  seasons   of 

1916-1917  and  1917-1918,  (on  opposite  page)  1918-1919  and  1919-1920.     Based  upon 

United  States  Weather  Bureau  Reports. 

OUTSIDE  TEMPERATURES:  Although  the  records  of  the  United  States 
Weather  Bureau  (See  Figure  2-1)  may  show  an  extreme  minimum  tempera- 
ture much  lower  than  that  usually  experienced  in  a  given  locality,  it  is  not 
customary  to  estimate  heating  requirements  with  that  extreme  tempera- 
ture as  a  basis. 

Generally,  the  average  minimum  temperature,  obtained  from  United 
States  Weather  Bureau  records  over  a  period  of  ten  years  or  longer,  is  the 
fundamental  consideration.  To  illustrate  the  necessity  for  considering  a 
period  of  years,  rather  than  to  establish  the  basis  on  the  result  of  two  or 
three  years,  charts  (Figure  2-2)  have  been  prepared  showing  the  minimum 

16 


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and  maximum  temperatures  for  each  day  of  the  heating  season  for  the 
winter  months  of  1916-1917  to  1919-1920  for  New  York  City. 

These  charts  show  the  extreme  variation  of  minimum  temperature 
for  different  winters  and  indicate  that  a  safe  average  cannot  be  obtained 
without  having  records  of  a  long  period  of  years  for  consideration.  They 
are  shown  also  as  a  suggested  form  for  the  preparation  of  similar  data  from 
Weather  Bureau  reports  for  any  locality  where  it  is  desired  to  study  the 
temperature  conditions  upon  which  the  design  of  a  heating  system  is  to 
be  based. 

It  is  possible  to  operate  the  most  effective  types  of  steam  heating 
systems  with  a  slight  increase  in  steam  pressure,  which  results  in  an 
increased  rate  of  heat  emission  from  the  radiating  surfaces.  This  flexi- 
bility is  advantageous  during  short  periods  of  very  cold  weather. 


17 


FLOOR  PLANS,  ELEVATIONS  AND  CROSS-SECTIONS:  To  properly  design 
the  heating  system  for  one  or  more  buildings,  complete  floor  plans  and  suffi- 
cient elevations  and  cross-sections,  showing  details  of  construction,  materials, 
etc.,  must  be  available  for  accurately  calculating  the  heating  requirements. 

In  designing  heating  systems  for  existing  buildings,  accurate  data  may 
be  obtained  by  survey,  but  with  designs  of  new  buildings  certain  assump- 
tions are  necessary.  These  may  or  may  not  be  justified  when  construction 
is  complete.  A  frequent  element  of  error  lies  in  change  from  original  plans 
without  proper  consideration  for  the  effect  upon  the  heating  system. 

These  possible  discrepancies  in  construction  and  deviation  in  design 
from  original  plans  make  it  quite  necessary  for  the  designer  of  the  heating 
system  to  place  himself  on  record  as  to  the  basic  factors  of  his  calculation. 

INSIDE  TEMPERATURE  REQUIREMENTS:  The  temperature  to  be  main- 
tained and  the  lowest  permissible  temperature,  are  usually  governed  by  the 
use  for  which  the  enclosure  is  intended. 

Inside  temperatures  are  usually  determined  at  the  breathing  line  and 
not  closer  than  5  ft.  from  the  most  exposed  wall. 

The  important  considerations  for  decision  lie  in  the  following  questions: 

Is  the  heat  to  be  maintained  continuously  24  hours  per  day  or  for  stated 
portions  of  the  total  24  hours? 

If  intermittent  heating,  how  long  a  time  may  be  allowed  to  raise  the 
room  temperature  to  the  required  maintained  temperature? 

Through  how  long  a  period  will  heat  be  shut  off  and  how  low  may 
the  room  temperature  become  during  this  closed  down  period? 

The  following  table  indicates  the  usual  range  in  maintained  tempera- 
tures desired  for  various  classes  of  occupancy,  but  it  should  be  kept  in  mind 
that  temperature  is  largely  a  matter  of  individual  preference  so  that  such  a 
table  can  be  considered  only  as  a  guide  in  the  final  selection. 

Table  2-1.    Temperature  for  Various  Rooms  in  Deg.  Fahr. 

Bath  rooms 75  to  85 

Churches .60  to  70 

Entrance  halls  to  public  buildings .  50  to  60 

Factories 60  to  70 

Foundries ..  50  to  60 

Gymnasiums ..  60  to  65 

Homes  for  aged 80 

Hospitals .  .72  to  75 

Lecture  halls .  60  to  70 

Living  rooms ..  68  to  72 

Machine  shops 60  to  70 

Offices .68  to  72 

Operating  rooms 70  to  90 

Paint  shops .80  to  90 

Prisons,  day  confinement ..  60  to  65 

Prisons,  night  confinement 50  to  55 

Public  buildings 68  to  72 

Schools 

Shops  (stores) .  ..  50  to  65 

Swimming  halls ..  70  to  75 

Vestibules  for  stores  and  office  buildings .  70  to  80 

18 


The  relative  humidity  of  the  atmosphere  which  is  likely  to  exist  in  any 
room  or  building  has  a  bearing  upon  the  desirable  inside  temperature. 

For  a  living  apartment,  a  normal  temperature  of  70  deg.  fahr.  and  rela- 
tive humidity  of  50  per  cent  (about  4  grains  of  water  vapor  per  cubic  foot  of 
content)  is  considered  by  most  authorities  to  be  a  very  satisfactory  condition 
of  the  air.  If  the  temperature  is  lower  than  70  deg.,  the  relative  humidity 
should  be  higher  than  50  per  cent  or  if  the  temperature  is  higher,  the  relative 
humidity  should  be  lower  if  the  same  effect  of  comfort  to  the  occupant  is  to 
result. 

It  is  usual,  however,  that  the  relative  humidity  is  found  to  be  much  less 
than  50  per  cent  in  living  apartments  heated  to  70  deg.  fahr.  and  has  been 
observed  to  be  as  low  as  28  per  cent.  With  very  low  relative  humidity  the 
effect  upon  the  occupant  is  a  feeling  of  chilliness  even  though  the  temperature 
may  be  increased  to  78  or  80  deg.  fahr.  This  cooling  effect  is  due  to  the 
rapid  evaporation  of  moisture  from  the  occupant's  skin,  which  is  brought 
about  by  the  low  vapor  pressure  of  the  atmosphere.  Conversely,  where 
extremely  high  relative  humidity  exists,  a  temperature  of  70  deg.  fahr. 
might  feel  oppressively  hot  to  the  occupant. 

CONTENTS  AND  USE  OF  ENCLOSURE  :  A  very  important  consideration 
for  the  designer  is  that  of  the  materials  and  machinery  within  the  enclosure, 
and  their  capacities  for  absorbing  heat.  This  has  an  important  bearing 
upon  the  permissible  time  limit  for  warming  up. 

Large  quantities  of  material  or  machinery  having  a  high  heat  content 
will  prolong  the  time  for  warming  and  will  have  an  opposite  effect  of  re- 
tarding the  loss  of  temperature  when  the  heat  supply  is  cut  off. 

For  consideration  of  this  factor,  the  designer  should  have  details  of  the 
weight  and  substance  of  each  of  the  various  items  of  machinery  and  materials. 
With  this  data  and  a  table  of  specific  heats  of  substances  such  as  on  pages 
342-3,  the  total  heat  contents  or  heat-absorbing  capacities  which  influence 
the  warming-up  period  can  be  determined. 

Likewise,  the  designer  should  determine  the  total  heat  given  off  by  the 
operation  of  the  machinery,  motors,  lights,  etc.,  although  this  is  not  of  so 
much  importance  in  buildings  where  the  temperature  requirements  are  those 
to  be  maintained  during  periods  when  machines,  etc.,  are  not  in  operation. 

In  schools,  theaters,  auditoriums,  churches,  etc.,  where  large  numbers 
of  persons  may  gather,  it  is  necessary  to  allow  for  the  heat  given  off  by  the 
human  bodies  if  overheating  is  to  be  prevented.  In  such  cases,  ventilation 
is  usually  required  to  remove  the  bodily  heat  with  its  excessive  humidity. 

In  manufacturing  plants,  portions  of  buildings  often  require  unusual 
quantities  of  heat  to  warm  the  large  amounts  of  air  which  replace  that  drawn 
from  the  rooms  through  exhausting  fans  on  grinders,  dryers  and  similar 
apparatus.  This  condition  requires  a  careful  investigation  of  the  factors 
involved  in  the  unusual  rate  of  air  change. 

CHARACTER  AND  LOCATION  OF  HEATING  SURFACES:  The  selection  of 
the  radiation  from  a  choice  of  direct,  indirect,  direct-indirect  or  blast  type 
depends  largely  upon  the  use  for  which  the  enclosure  is  intended,  the  ven- 

19 


tilation  requirements,  the  local  building  laws,  school  and  labor  codes,  and 
other  general  considerations. 

Whether  pipe  coils,  cast-iron  wall  radiation  or  column  cast-iron  radi- 
ators are  to  be  used  for  direct  heating  is  usually  a  question  of  availability 
of  materials,  cost  of  installation  and  the  esthetic  effect  required. 

The  selection  of  the  type  and  location  of  the  different  radiating  units 
may  best  be  determined  by  a  study  of  the  plans  and  elevations  of  the  build- 
ing to  be  heated. 

LOCATION  OF  SUPPLY  AND  RETURN  LINES  :  In  installations  of  the  type 
for  hotels,  hospitals,  office  buildings  or  other  public  buildings  with  finished  or 
decorated  walls  it  is  customary  to  conceal  the  steam  and  return  risers,  and  their 
run-outs  to  radiators,  in  the  wall  and  floor  construction.  In  factory  instal- 
lations and  other  less  expensive  types  of  construction  these  lines  are  exposed 
and  in  many  instances  they  are  used  as  prime  radiating  surfaces. 

In  cases  where  the  outlets  from  the  risers  are  taken  below  the  level  of 
entrance  to  the  radiators  it  is  essential  that  the  run-outs  shall  be  so  graded 
that  the  condensation  will  flow  back  by  gravity  into  the  risers  regardless  of 
the  maximum  velocity  of  steam  which  may  flow  in  the  opposite  direction. 
It  is  therefore  of  prime  importance  that  the  maximum  velocity  shall  be  kept 
well  below  that  at  which  the  condensation  will  be  swept  along  with  the  steam. 
This  important  feature  of  design  is  discussed  in  further  detail  in  Chapter  12. 

A  down-feed  system  of  supply  is  preferable  wherever  building  conditions 
will  permit,  since  the  condensation  will  then  flow  in  the  same  direction  and 
will  be  assisted  by  the  flow  of  steam  as  well  as  by  gravity.  This  permits  the 
use  of  smaller  supply  risers  and  run-outs  due  to  the  higher  velocities  of 
steam  flow  which  are  permissible. 

Return  run-outs,  risers  and  mains  must  grade  in  the  direction  of  flow  of 
condensation  to 'some  low  point  or  points  from  which  the  condensation  will 
be  returned  to  the  source  of  steam  supply  or  other  point  of  disposal. 


20 


CHAFFER  III 

Heat  Transmission 

THE  same  principle  of  transmission  of  heat  from  a  higher  to  a  lower 
temperature  that  makes  steam  heating  effective,  also  functions  in  the 

transmission  of  heat  through  materials  of  construction  to  make  such 
heating  necessary. 

Heat  seeks  equilibrium,  and  consequently  there  is  a  transfer  of  heat 
from  a  higher  to  a  lower  temperature  with  greater  or  less  rapidity,  depending 
upon  the  difference  in  temperature  and  the  character  and  thickness  of  the 
material  through  which  it  flows. 

For  the  purpose  of  estimating  the  heat  losses  from  enclosures,  numerous 
tests  and  deductions  from  practice  have  been  made  to  determine  the  rate 
of  heat  transmission  through  the  various  types  and  materials  of  surfaces 
used  for  enclosing  space.  So  many  variables  enter  this  problem  that  it  is 
impossible  to  predict  the  heat  transmission  exactly  unless  all  of  the  peculiari- 
ties of  any  case  under  consideration  have  been  previously  determined. 

Tables  of  heat  transmission,  therefore,  attempt  to  provide  for  average 
conditions  of  construction  of  the  enclosing  substances.  Due  regard  must 
be  given  to  the  facility  with  which  heat  is  absorbed  and  removed  from  the 
surfaces  of  the  enclosing  substances,  and  to  the  heat  which  is  transmitted 
through  them,  due  to  the  difference  between  the  temperatures  existing  at 
their  surfaces,  which  may  be  termed  "heat  head." 

This  heat  head  has  been  considered  in  many  formulae  as  a  constant 
increase  per  degree  of  temperature  difference.  As  the  result  of  tests  with 
the  same  substance  under  various  temperature  differences  this  deduction 
has  been  proved  to  be  incorrect.  Higher  temperature  differences  cause 
greater  transmission  per  degree  difference  than  lower  temperature  differences. 

The  probable  variation  in  heat  transfer  under  various  conditions  of 
heat  head  is  shown  in  Fig.  3-1.  The  rate  of  transfer  for  any  difference 
between  inside  and  outside  temperatures  other  than  70  deg.  is  expressed 
as  a  percentage  of  that  at  70  deg.  difference. 

The  discussion  of  Rates  of  Heat  Transmission  in  this  book  recognizes 
the  following  fundamental  conditions: 

(1)  The  maintained  inside  temperature  is  that  normally  existing  at 
the  breathing  line  (5  ft.  above  the  floor)  and  about  5  ft.  from  the  wall. 
The  breathing  line  is  more  often  mentioned  hereafter  as  the  datum  line. 

(2)  The  basic  rate  of  transmission  for  any  substance  is  the  number  of 
B.t.u.  which  will  be  transmitted  in  an  hour  through  each  square  foot  of 
surface  of  that  substance  when  the  outside  temperature  is  zero  and  the 
maintained  inside  temperature  is  70  deg.  fahr. 

(3)  From  the  above  it  will  be  evident  that  the  basic  rate  is  that  which 
is  transmitted  at  the  datum  line. 

21 


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3QISNI   Q3NIV1NIVW  CNV  3015100  NI33M139  30N3d3JJia 
22 


In  many  structures  with  a  coiling  height  of  20  to  30  ft.,  with  no 
mechanical  agitation  and  a  low  transmission  rate  through  the  roof,  the  aver- 
age increase  in  temperature  recorded  above  the  datum  line  to  a  point  close 
under  ceiling  has  been  fully  1  dog.  fahr.  per  ft.  In  other  buildings  of  similar 
height  with  cold  roof  the  average  rise  has  been  less  than  ^  deg.  per  ft. 

The  downward  circulation  set  up  by  the  absorption  of  heat  from  the 
air  near  cold  enclosing  surfaces  tends  to  agitate  the  entire  contents  and 
reduce  the  stratification  effect.  The  greater  the  difference  between  the 
exterior  and  the  maintained  interior  temperature,  the  greater  the  agitation 
and  the  less  the  heat  rise  per  unit  of  height  above  the  datum  line. 

In  estimating  heat  flow,  the  average  height  above  the  datum  line  for 
each  class  of  service  should  be  considered.  Due  to  the  increase  in  tempera- 
ture above  the  datum  line,  the  transmission  rate  for  each  surface  will  cor- 
respond to  that  of  the  temperature  of  the  strata  at  the  average  height  above 
datum  of  such  surface  rather  than  that  at  datum  line. 

Where  the  space  above  the  ceiling  is  heated,  the  temperature  of  the 
strata  closest  to  ceiling  will  be  the  highest.  In  such  case  it  is  usual  to  con- 
sider the  average  temperature  to  be  that  midway  between  the  datum  line 
and  the  upper  edge  of  the  vertical  enclosing  surface  and  obtain  from  Figure 


r-75    - 


-83 


81 
-80 

7<J 
-78 
-77 
-7G 
-73 
-74 

7:! 
-72 

71 
-70 

M 

US 

07 


OMJ.> 


Line  of  maintained  inside 
_  Temperjture  or  Floor  Datum  Line 


I  i.'    .'i-2.      IlliistrittiiiK  tx-at  stratification 


3-1,  the  percentage  to  be  applied  to  the  basic  transmission  rate  of  the 
surface  under  consideration. 

In  the  case  where  the  space  above  the  roof  or  ceiling  is  cold,  the  tem- 
perature of  the  strata  ceases  to  increase  beyond  a  height  somewhat  below 
such  roof  or  ceiling;  the  distance  depending  on  the  rate  of  transmission 
through  the  roof.  In  this  case  it  is  necessary  to  assume  two  limits  when 
correcting  the  basic  factor  of  the  enclosing  surface  to  allow  for  stratification. 
It  is  usual  to  consider  the  average  temperature  in  this  case  as  that  midway 
between  basic  level  and  a  level  five  feet  under  the  cold  roof. 

The  temperature  does  not  always  continue  to  increase  in  equal  amount 
per  unit  of  elevation  above  the  datum  line  and  in  very  high  rooms  the  level 
at  which  it  ceases  to  increase  is  likely  to  be  more  than  5  ft.  below  the  cold 
ceiling. 

In  rooms  with  a  ceiling  height  over  10  ft.  where  air  is  mechanically 
agitated,  there  will,  in  most  cases,  be  a  higher  average  temperature  than  that 
at  the  datum  line  with  a  consequent  increase  in  transmission  rate;  this,  how- 
ever, will  be  materially  less  than  in  cases  of  similar  height  where  there  is 
no  mechanical  agitation. 

Heat  losses  through  monitors  must  be  specially  considered.  In  such 
cases  it  is  usual  to  install  heating  surfaces  within  the  monitor  construction, 
and  for  that  reason  the  entire  monitor  construction  should  be  considered 
as  an  individual  unit  of  enclosure  with  an  imaginary  floor  across  the  space 
between  the  lower  edges  of  its  vertical  sides. 

However,  the  factors  for  stratification  for  figuring  heat  losses  from 
monitors  should  disregard  the  5 -ft.  datum  line;  that  is,  assuming  that  the 
temperature  at  this  imaginary  floor  line  is  approximately  70  deg. 

In  the  cases  where  consideration  must  be  given  to  the  transmission 
of  heat  through  surfaces  at  a  level  beneath  the  datum  line  it  is  advisable 
to  disregard  stratification  and  estimate  the  heat  transmission  at  the  difference 
between  the  temperature  at  the  datum  line  and  at  the  other  side  of  exposed 
surface. 

Basic  factors  for  average  height  above  datum  should  be  fixed  on  the  basic 
temperature  difference  of  zero  outside  and  70  deg.  fahr.  maintained  inside. 

If  the  outside  temperature  for  which  any  particular  enclosure  is  figured 
is  different  from  zero,  or  if  the  temperature  to  be  maintained  at  the  breathing 
line  is  more  or  less  than  70  deg.,  or  if  both  inside  and  outside  temperatures 
arejdifferent  from  the  basic  tables,  the  rates  of  transmission  should  be  ad- 
justed for  the  new  difference  in  temperature  by  factors  obtained  from  Figure 
3-1,  and  applied  to  all  transmission  losses  through  the  structure. 

It  is  hoped  that  in  the  next  edition  of  "Steam  Heating,"  the  result  of 
tests  now  under  way  will  be  sufficiently  complete  to  indicate  the  probable 
maximum  degree  of  stratification  likely  to  be  encountered  in  the  erecting 
shops  and  other  structures  with  high  ceilings,  which  are  with  increasing 
frequency  presenting  their  problems  to  the  Heating  Engineer. 

To  obtain  the  maximum  transmission  rate  due  to  the  average  height 
above  the  floor  of  various  surfaces  mentioned  in  tables  on  following  pages,  the 
formulae  on  next  page  should  be  employed  and  a  probable  maximum  value 
given  to  S,  the  rate  of  heat  increase  due  to  stratification. 

24 


'ti,  doors,  walls,  and  other  vertical  surfaces 

T!  =  T  +  S  (  — •  +  D  —  5  )  Formulae  3-1 

Hoofs,  ceilings,  or  oilier  horizontal  or  sloping  surfaces 

Where  upper  side  is  cold  Where  upper  side  is  heated 

T,  =  T  +  S(H2-  10)  T,  =  T  +  S(H2-5) 

in  which 

T  =  temperature  at  the  datum  line. 

Ti  =  average  temperature  due  to  stratification  at  mean  height  of  the 

surface  above  datum 
S    =rate  of  heat  increase  above  datum,  in  degrees  per  foot,  due  to 

stratification. 

H  =  height,  in  feet,. of  upper  level  of  vertical  surface  above  lower  edge. 
H2  =  average  height  in  feet  above  floor  of  nearly  horizontal  surface. 
D  =  height  in  feet  above  floor  of  lower  level  of  vertical  surface. 

BASIC  FACTORS:  Assuming  a  value  of  S  in  Formulae  3-1,  Ti  may  be 
found  for  any  given  condition  and  by  referring  this  TI  to  Figure  3-1,  the 
percentage  to  be  applied  to  the  basic  rate  may  be  found.  If  the  tempera- 
ture conditions  are  other  than  basic  (zero  deg.  to  maintained  70  deg.)  the 
rates  of  transmission  for  heights  other  than  basic  should  be  adjusted  to 
the  new  temperature  difference. 

The  heat  transmission  values  in  the  following  tables  have  been  proven 
by  experience  to  be  approximately  correct.  These  values  may  need  revision 
when  results  are  published,  of  tests  contemplated  by  the  Research  Bureau 
of  the  American  Society  of  Heating  and  Ventilating  Engineers. 

Table  3-1.     Walls,  Clapboard 

Construction  Ba  sic  f ac  t  or,  0  to  70  dec. 

Clapboard  on  studs,  hare 50 

Clapboard  on  studs,  with  lath  and  plaster 35 

Clapboard  and  paper  on  studs,  with  lath  and  plaster 30 

Clapboard  on  studs,  with  l-in.  sheathing,  bare 40 

Clapboard  on  studs,  with  l-in.  sheathing,  papered 35 

Clapboard,  with  l-in.  sheathing  on  studs,  latn  and  plaster 25 

Clapboard  and  paper,  with  l-in.  sheathing  on  studs,  lath  and  plaster 20 

Clapboard  on  studs,  with  brick  fill,  bare 28 

( '.  hi  |  il«  >,inl  on  studs,  with  brick  fill,  papered 

Clapboard  on  studs,  with  brick  fill,  lath  and  plaster 22 

Clapboard  and  paper  on  studs,  with  brick  fill,  lath  and  plaster 20 

Clapboard  and  sheathing  on  studs,  sawdust  fill,  lath  and  plaster 15 

Clapboard,  paper  and  sheating  on  studs,  sawdust  fill,  lath  and  plaster 10 

Tul.lr    S-2.       Interior    \\  ;i!ls 

Construction  Bask  factor,  0  to  70  del . 

I'histiT.  wood  lath,  studs,  wood  lath  and  plaster 24 

Plaster,  metal  lath,  studs,  metal  lath  and  plaster 28 

Studs,  wood  lath  and  plaster 42 

Stuils.  metal  lath  and  plaster 48 

4-In.  hollow  tile  plastered  one  side 40 

•l-ln.  hollow   tile  plastered  both  sides 35 

2-In.  g>  psiiin  hliM-k  plastered  one  side 45 

2-In.  gypsum  block  plastered  Ix>th  sides 42 

25  * 


Table  3-3.     Walls,  Stucco  on  Studs 

Table  3-6.     Walls,  Hollow  Tile  Faced  with 
Brick 

Construction                    ^'to  70° 

Thickness                       Basic  factor 
in  inches                         0  to  70° 

f> 

o 

i 

, 

Plaster     Stucco   on    lath,    with    wood 
lath  and  plaster  on  the  inside      10 

*-a* 

i-  T  j 
*-i-^ 

—  •" 

n 

l(ri<k                    Tile              Plain 

4                         4                   25 
4                         8                   20 
4                       12                   14 
4                       16                   10 

v^  Studs 

• 

o 

1 

Stucco  on   metal    lath,   with 
Blaster     metal  lath  and  plaster  on  the 
inside                                               15 

u 
n 

• 

Studs 

L    - 

Table  3-4.    Walls,  Corrugated  Iron 

*B>|<  T> 

Plastered  inside 

-,                                         Basic  factor 
Construction                       0  to  70. 

4                          4                    20 
I                        8                   16 
4                       12                   12 
4                       16                     9 

n 
n 

Cor.jl 

Iron    ( 

Coi. 

ron  "* 

Iron  V 
<f 

r  leafs      Plain   loose   construction   on 
Air        framework                                    125 

)  ^teaks     Tight  construction  on  fraine- 
/no  Air    work                                                   90 

^ood      On    1-in.    tongue-and-groove 
sheathing                                        45 

n 

D 

1  ' 

t 

R 

n 

Furred  and  plastered  inside 

4                         4                   16 
I                         8                   H 
4                       12                   12 

Is             4                       16                     8 

n 

Table  3-5.     Walls,  Brick 

u 

. 

Thickness                     Basic  factor 
in  inches  T                         0  to  70° 

Table  3-7.    Walls,  Concrete  Faced  with 
Brick  4-in.  Thick 

Plain 

4                             45 
8                             30 
12                             22 
16                             18 
20                             16 
24                             14 
28                             12 
32                               10 
36                               9 

<    T    > 

Thickness                      Basic  factor 
in  inches                          0  to  70° 

«e-»|«-C->)              Brick             Concrete           Plain 

1 

1  

pr^| 

4                         4                   35 
4                         8                   28 
4                       12                   22 
t                       16                   18 

I 

1 

Plastered  inside 

4                               40 
8                               28 
12                               20 
16                               15 
20                               14 
24                               12 
28                               11 
32                                 10 

—  —  - 

i 

-B^f 

M 

Plastered  inside 

4                         4                   32 
4                         8                   25 
4                       12                   19 
4                       16                   16 

u 

13 

1 

- 

<c 

] 

' 

I 

36                                   8 

* 

\'..    •; 

§ 

Furred  and  plastered  inside 

__k 

4                               30 
8                               20 
p|                 12                               15 
16                               12 
20                               11 
'•                 24                                 9 
28                                 8 
32                                 7 

0£ 

r 

w  — 

*c* 

$i?-\ 

?,>*;•' 

Furred  and  plastered  inside 

r— 
\ 

4                         4                   25 
4                         8                   20 
4                       12                   16 
4                       16                   12 

1 

:,v?;° 

1 

1 

i  °j  . 

2f. 


Table  3-8.     Walls,  Hollow  Tile 


Thickneu 
in  inches  T 


Basic  factor 
0  to  70° 


n 


n 


Pliiin 


4 

45 

6 

40 

8 

28 

10 

24 

12 

18 

Bf 

Plastered  inside 

4 

6 
8 
10 
12 

40 
35 
25 
20 
16 

nf 

r     "™i    ; 

-C33.: 

tr 

Stucco,  plastered  inside 

1                      4 
6 
8 
10 
12 

35 
32 
22 
18 
15 

n 

o 
n 

•  L 

k-r-» 

Stucco,  furred  and 

plastered  inside 

30 
28 
20 
16 
14 

n 

4 
6 
8 
10 

of 

12 

Table  3-9.    Walls,  Concrete  4-in.  Thick 
Faced  with  Stone 


Table  3-10.    Walls,  Sandstone  or  Limestone 


Thickness 
in  inches  T 

Basic  factor 
0  to  70° 

Plain 

4 

6 
8 
10 
12 
16 
20 
24 

75 
65 
55 
50 
45 
38 
33 
27 

HI 

4 
6 
8 
10 
12 
16 
20 
";              24 

67 
58 
49 
45 
41 
34 
29 
24 

im 

i*  '  *i 

Stucco,  furred  and 

plastered  inside 

1                    * 
6 

8 
10 

50 
43 
37 
33 
30 
25 
22 
18 

$$ 

i:7Tvr?i:r 

m 

12 
16 
20 
a              24 

Table  3-11.    Walls,  Hard  Stone  or  Concrete 


Thickness 
in  inches 


Basic  factor 
0  to  70° 


Concrete 


Stone 


Plain 


m 

wE 

4 
4 

4 

8 

50 
40 

4 

12 

35 

* 

4 

16 

27 

| 

Plastered  inside 

4 

4 

45 

yi'1/' 

^ 

4 

8 

36 

$£ 

4 

12 

32 

K 

4 

16 

24 

Furred  and  plasU-red  inside 


4 
4 

4 

1 


4 

8 

12 

16 


33 

27 
23 
18 


Thickness 
in  inches  T 

Basic  factor 
0  to  70° 

Plain 

' 

1 

4 
6 
8 
10 
12 
16 
20 
24 

70 
60 
50 
45 
40 
35 
27 
20 

Plastered 

inside 

54 
45 
41 
36 
32 
24 
18 

5? 

"SAi 

<Q- 

6 
8 
10 
12 

24 

Stucco,  furred  and  plastered 

t  ^^/V 

•pi                  4 
6 
8 
10 

111                 12 

16 
fa                 20 
1  M                24 

17 

III 

30 
27 
23 
18 
13 

27 


Table   3-12.     Windows 


Construction 

Basic            The  factors 
oto°70°     mission  rates  i 
floor  and  a  tt 

in  this  table  are  for  trans- 
it the  datum  line  5  ft.  from 
:mperature  of  70  deg.   fahr. 
lire  TI   at  the    centre  of   a 
height  above  the  floor  will  be 

Lte   of    heat   increase    al>ove 

Wood 

.  _       Wood  sash, 

The   temperati 
75           window  of  any 

42 
Where  S  =  rt 

I          I  •  
Glass 

Wood 

'  ":  '       single  glazed 
,    Glass             \Vood  sash, 

Glass    ' 

s: a  SMSr1-    »          .Jr^feK.- 

G|MS-  H  =  the  number  of  feet  of  height 

Hollow  Metal  Hollow  metal  sash,  of  th.e  "PPer  e^e  of  window 

=-^-        -=        ^.e^ed  80  D-StLrarfty* 

of  the  lower  edge  of  window 

Solid  metal  sash,  opening  above  the  floor, 

double  glazed  65  (See  Figure  3-2) 

With  Ti  established,  the  factor  for  cor- 

Hollow  metal  sash,  reeling  the  tabular  values  will  be  deter- 

double  glazed  45  mined  from  Fig.  3-1.    Apply  this  corrected 

factor  to  the  entire  area  of  window  opening. 


MONITORS  must  be  considered  as  separate  problems,  as  if  they  are  structures  of  themselves  with 

theoretical  floors  at  the  level  of  the  base  of  the  monitor.  Their  transmission  losses  and  the  sizing  and  placing 

of  radiating  surfaces  should  be  figured  accordingly.    The  factor  should  disregard  the  usual  5-ft.  datum 
line.   That  is,  assume  that  the  temperature  at  this  imaginary  floor  line  is  70  deg.  fahr. 

Table  3-13.     Doors  and  Wood  Partitions 

Construction  Basic  factor,  0  to  70  ° 

j^-In.  to  1-in.  thick,  tongued-and-grooved 45 

1     -In.  to  l}^-in.  thick,  tongued-and-grooved 40 

lJ4-In.  to  IJ^-in.  thick,  tongued-and-grooved 35 

1  l/2-ln.  to  2-in.  thick,  tongued-and-grooved 30 

-In.  to  2J^-in.  thick,  tongued-and-grooved 25 

2l/2-ln.  to  3-in  thick,  tongued-and-grooveH .  .        20 

Table  3-14.     Roof  Construction 

Construction  Basic  factor.  0  to  70* 

Flat  tile  on  strips 75 

Flat  tile  on  sheathing 45 

Slate  on  strips 78 

Slate  on  sheathing  and  paper 35 

Corrugated  iron  on  strips 125 

Corrugated  iron  on  sheathing 45 

Tin  on  strips 110 

Tin  on  sheathing 40 

Tin  on  sheathing  with  paper 30 

Shingles  on  strips 60 

Shingles  on  sheathing 30 

Shingles  on  strips  over  tar  paper  and  sheathing '••••.  15 

Reinforced  concrete  composition  2-in.,  paper,  tar  and  gravel 50 

Reinforced  concrete  composition  3-in.,  paper,  tar  and  gravel 45 

Reinforced  concrete  composition  4-in.,  paper,  tar  and  gravel 40 

Hollow  tile  4-in.,  paper,  tar  and  gravel 20 

Hollow  tile  6-in.,  paper,  tar  and  gravel 18 

Metropolitan  3-in.,  paper,  tar  and  gravel 20 

Metropolitan  4-in.,  paper,  tar  and  gravel 15 

1-In.  wood  with  5  to  8-ply  paper,  tar  and  gravel 20 

1-In.  wood  with  felt  roofing 25 

l}^-In.  wood  with  5  to  8-ply  paper,  tar  and  gravel 18 

2-In.  wood  with  5  to  8-ply  paper,  tar  and  gravel 15 

2J^-In.  wood  with  5  to  8-ply  paper,  tar  and  gravel 12 

2-In.  Federal  cement  tile,  paper  and  tar  and  gravel 50 

28 


Table  3-15.     Roof  Glass  and  Skylights 
The  surface  to  be  considered  is  the  total  surface  of  glass  and  frame 


Construction 


Basic  factor,  0  lo  70° 


Wood 


-I        1      Wood  sash,  single  glazed. 


Wood 


^     r     ~1      Wood  sash,  double  gla/ed . 


Solid  metal  sash,  single  glazed .  . 
Hollow  metal  sash,  single  glazed .  . 
Solid  metal  sash,  double  glazed .  . 
Hollow  metal  sash,  double  glazed  . 


42 
90 
80 
65 
45 


Glass 


Table  3-16.     Floors  Above  Cold  Space 

The  factors  are  for  0  to  70  deg.  difference  in  temperatures.     For  any  other  difference,  the  basic  factor 
should  be  corrected  in  accordance  with  chart,  Fig.  3-1 


Above  cold  space 


Description 


Basic  factor,  0  to  70° 


U- 


Wood 
Joists 


Wuud 
Joists 
Wood 


Wood 
Joists 

Wood 


joists 


lath  and  Plaster 
Wood     A 


{-  r-  lo[$t~~          Wood     '      Joist  •£$£ 


Mill  construction,  3-in.  wood  and  paper  plus  Ji-in.  surface  .  12 

1-ln.  single  wood  floor  on  joists 23 

^  2-ln.  double  wood  floor  on  joists 15 

1-In.  single  wood  floor  on  joists  with  lath  and  plaster 11 

2-ln.  double  wood  floor  on  joists  with  lath  and  plaster 10 


Lath  and  Plaster 
Wood     . 


TT^ 


Insulation 
Wood 


Wood    "          Joist"    I 


'      Lath  and  Plaster 


Jin.  double  wood  floor  on  joists  with  insulation  and  lath  and 
plaster 4 


Wood 

Concrete 
Wood      , 

Wood 

. 

""•VS 

Concrete 


Reinforced  Concrete 


Reinforced  Concrete  -' 


Reinforced  Concrete 


Reinforced  Concrete 


2-ln.  double  wood  floor  on  4-in  fireproof  concrete 6 

)      1-ln.  wood  flooring  on  double  wood  and  4-in.  fireproof  con- 
crete   4 

';•- '•'>'--  Ti      Hn.  concrete  slab,  metal  reinforced 70 

6-In.  concrete  slab,  metal  reinforced 60 

8-In.  concrete  slab,  metal  reinforced 50 

10-In.  concrete  slab,  metal  reinforced 40 


29 


Table  3-17.     Floors  Laid  on  Ground 

These  factors  are  for  0  to  70  deg.  difference  in  temperature.  It  is  usual,  however,  to  assume  the 
temperature  of  the  ground  beneath  the  floor  as  50  deg.  fahr.  For  this  difference  the  above  basic  factor 
must  be  corrected  by  means  of  the  chart  in  Fig.  3-1 


Construction 


Basic  factor 
0  to   70° 


/^A  Y-^\  AiA /^/\ 

^fepefs^'  Ground' 


Wood-*  Waterproofing^ 

Concrete'' 
l"Wood-x  Paper 


^:^::fe^:V-A     '.-^. 

2"Wood 

Sleeper'' 

lv-:- 


Concrete 


Ground 
Concrete^ 


1-In.  single  wood  floor  on  wood  sleepers . 


2-In.  wood  floor  on  4-in.  water-proofed  concrete 7 


3-In.  double  wood  floor  with  paper  between  on  sleepers  in 
4-in.  concrete. .  .  4 


4-In.  concrete  floor  on  ground 22 


4-In.  concrete  floor  on  cinder  fill .  .  20 


GruunJ-1 


Concrete                                          Ground 
Briclo. 


1-In.  tile  floor  on  4-in.  concrete. . 


2%-ln.  brick  floor  on  4-in.  concrete .  . 


22 


20 


Table  3-18.     Ceilings 

The  factors  are  for  0  to  70  deg.  difference  in  temperatures.     For  any  other  difference,  the  basic  factor 
should  be  corrected  in  accordance  with  chart.  Fig.  3-1 


Construction 


Basic  factor 
0  to  70° 


-Joists 


Plaster 
Wood -A 


Joisls 


Wuod  Lath 


(Wood 


Plaster-^ 
Wood 


'Wood  Lath 


Plaster- 


Wood  lath  and  plaster  on  joists  .........................     42 


Metal  lath  and  plaster  on  joists  .........................     46 


g-,  1-In.  single  wood  floor  on  joists  with  wood  lath  and  plaster ...     18 


2-In.  double  floor  on  joists  with  wood  lath  and  plaster  ......     14 


-Joists - 


Metal  Ceiling 


1.1 


1-In.  single  wood  floor  on  joists  with  stamped  metal  ceiling  ...     25 
30 


CHAPTER  IV 

Air  Infiltration 

WIND  blowing  against  walls  causes  a  leakage  of  air  into  the  enclosure 
and  an  outward  leakage  from  the  enclosure  through  the  opposite 
sides.  Additional  leakage  is  caused  by  temperature  difference  within 
and  without  regardless  of  wind  velocity.  These  leakages  are  sometimes 
referred  to  as  air  change,  but  in  this  book  are  called  air  infiltration. 

\s  the  air  enters  and  leaves  the  enclosure  at  different  temperatures, 
sullicient  H.t.u.  or  heat  units  must  be  provided  to  heat  this  air  between  the 
two  temperatures.  Air  infiltration  therefore  becomes  one  of  the  important 
factors  in  the  determination  of  the  heat  requirements  of  a  room  or  an  en- 
closure. 

Some  rules  for  heat  requirements  of  an  enclosure  regard  that  portion 
due  to  air  infiltration  as  an  additional  quantity  to  be  based  upon  an  arbi- 
trary hourly  air  change  or  upon  a  certain  percentage  of  the  best  trans- 
mission factor. 

Examination  of  the  air  infiltration  shows  that  most  of  the  air  leaks  are 
around  the  doors,  windows  and  other  similar  openings.  The  quantity  that 
rxpresses  the  heat  requirements  due  to  this  infiltration  of  cold  air  should 
therefore  be  based  upon  the  sum  of  the  openings  through  which  this  leakage 
occurs,  rather  than  upon  the  area  of  the  doors,  windows  and  similar  openings 
of  the  structure. 

\ny  determination  of  the  quantity  of  air  infiltrated  must  take  into 
consideration  the  velocity  and  direction  of  the  wind  in  relation  to  the 
openings  of  the  enclosure.  Where  an  enclosure  has  openings  on  more  than 
one  side,  the  infiltration  for  all  openings  must  be  determined  and  the 
radiation  for  this  loss  proportioned  and  located  according  to  the  maximum 
degree  of  infiltration  that  may  occur  on  any  side.  This  method  will  give  an 
excess  of  radiation  on  the  sides  where  leakage  is  outward,  but  there  is  no  alter- 
nate without  hating  some  sides  of  the  room  feel  cool  at  some  wind  direction. 

In  small  rooms  having  window  exposures  on  more  than  one  side,  and 
which  ordinarily  can  be  heated  with  one  radiator,  it  is  only  necessary  to 
consider  the  infiltration  for  the  side  of  maximum  exposure  and  locate  the 
radiation  on  that  side. 

The  leakage  in  narrow  monitors  and  rooms  where  cold  drafts  will  not 
be  objectionable  may  be  considered  only  on  the  side  where  maximum  wind 
velocities  occur.  A  portion  of  the  heat  to  care  for  this  infiltration  can  then 
be  applied  to  the  other  side.  Where  the  wind  strikes  the  surface  at  an  angle, 
the  resultant  velocity  at  right  angles  to  the  surface  must  be  considered. 
This  is  equal  to  the  actual  velocity  times  the  sine  of  the  angle  of  incidence. 

Normally  the  same  maximum  wind  velocity  should  be  considered  on 
the  north  and  west  sides,  while  on  the  south  and  east  sides  one-half  of  these 
velocities  may  be  used  except  where  special  wind  conditions  exist. 


31 


A  suggested  extreme  condition  for  New  York  and  vicinity  would  be 
15  miles  per  hr.  wind  velocity  with  a  temperature  of  zero.  Generally  low 
wind  velocities  prevail  at  extremely  low  temperatures. 

The  many  variables  make  reference  to  experiment  more  reliable  than 
attempts  to  determine  theoretically  the  perimeter  air  infiltration  of  windows, 
doors  and  similar  openings.  Little  dependable  experimental  data  is  avail- 
able at  present,  but  such  as  is  now  obtainable  must  be  used  as  a  basis 
until  better  is  to  be  had. 

Experiments  on  air  infiltration  of  windows  have  been  made  by  using  a 
fan  to  direct  wind  velocities  against  a  test  window  set  in  the  side  of  a  tight 
enclosure  and  having  an  opening  for  pitot  tube  readings  on  the  opposite 
side.  Further  details  regarding  some  of  these  experiments  by  Whitten  will 
be  found  in  the  1908  Transactions  of  the  American  Society  of  Heating  and 
Ventilating  Engineers,  and  others  by  Voorhees  and  Meyer  in  the  1916 
Transactions. 

Similar  tests  are  being  conducted  by  the  Research  Bureau  of  the 
American  Society  of  Heating  and  Ventilating  Engineers  and  the  United 
States  Bureau  of  Mines.  In  these  tests  natural  air  velocities  are  used  and 
the  infiltration  determined  by  reduction  in  carbon-dioxide  content  of  air 
in  the  room.  A  preliminary  report  of  these  tests  describing  the  method  in 
detail  was  given  by  Mr.  O.  W.  Armspach  in  the  Journal  of  American  Society 
Heating  and  Ventilating  Engineers,  January,  1921. 

Figure  4-1  gives  the  approximate  leakage  in  cubic  feet  per  minute  per 
lineal  foot  of  sash  perimeter  for  double-hung  locked  windows,  with  and 
without  metal  weather  strips. 

The  type  and  construction  of  the  windows  to  be  used  should  be  definitely 


•2  3  4  5  U  7  8 

AIR  INFILTRATION  IN  CUBIC  FEET  PER  MINUTE  PER  LINEAL  FOOT  OF  APERTURE 

Fig.  4-1.     Air  infiltration  for  double-hung  windows 
32 


10 


known  before  the  infiltration  is  estimated  and  this  data  recorded  in  a  similar 
manner  to  data  regarding  the  type  of  wall,  roof  or  other  construction  of  the 
enclosure. 

Due  allowance  should  he  made  for  special  sash.  The  meeting  rail 
must  he  considered  in  measuring  the  perimeter  of  double-hung  sash. 

In  windows  with  steel-section  frames  properly  bedded,  only  the  perim- 
eter of  that  portion  which  opens,  or  the  ventilating  sash,  need  be  considered. 

In  industrial  plants  where  it  is  intended  to  install  mechanical  exhaust 
systems  for  removing  dust  or  fume-laden  air,  special  means  must  be  provided 
to  care  for  the  corresponding  increase  in  infiltration  as  described  on  page  65 
of  Chapter  7. 

For  well-fitting  doors  the  average  window  values  can  be  used,  but 
for  sliding  and  similar  poorly  fitting  doors,  as  used  in  industrial  buildings, 
the  values  for  a  poor  window  should  be  used. 

The  leakage  values  as  read  from  Figure  4-1  when  multiplied  by  60  x 
0.086-1  (density  of  air  at  zero)  x 0.2375  (sp.  ht.  of  air),  will  give  the  heat 
units  per  hour  required  to  warm  the  infiltrated  air  from  1  ft.  of  perimeter, 
1  deg.  fahr. 

Example:  Assume  an  average  double-hung  window  3  ft.  wide  by 
6  ft.  high  with  a  perimeter  of  21  ft.,  outside  temperature  zero,  inside  tempera- 
ture 70  deg.  fahr.  with  wind  velocity  of  15  miles  per  hr.  Referring  to 
Figure  4-1,  the  leakage  per  foot  of  perimeter  is  found  to  be  1.60.  Then  21x 
1.60x60x0.0864x0.2375x70  =  2893  B.t.u.  per  hr.  required  to  heat  the  air 
infiltration  from  this  window. 

The  following  tables  will  be  found  useful  in  determining  the  heat 
units  required  to  care  for  the  infiltration.  These  values  are  for  plain  double- 
hung  windows.  If  equipped  with  a  good  metal  weather  strip,  use  20 
per  cent  of  the  tabulated  values. 

Table  4-1.     B.t.u.  per  Hour  Required  per  Lineal  Foot  of  Perimeter  for  Windows 


Wind  vel. 
Miles  per  hr. 

Infiltration 
Cu.  (t.  per  min. 
per  ft.  of 
perimeter 

Temperature  difference  inside  and  outside  of  enclosure 
50°                       60°                         65°                         70°                         80° 

Good 
window 

5. 

7.5 
10. 
15. 

•20 

.36 
.54 

.72 
1.08 
1.42 

22 
32 

44 

66 
87 

27 
39 
S3 
80 
105 

29 
42 
58 
86 
114 

31 
45 
62 
93 
122 

35 
52 
71 
106 
140 

Average 

window 

5. 
7.5 
10. 
15. 
20. 

.56 
.85 
1.12 
1.68 

2.22 

34 
52 
69 
103 
137 

41 
63 
83 
124 
164 

45 
68 
90 
134 
178 

48 
73 
97 
145 
191 

55 
84 
110 
165 
219 

Poor 

window 

5. 
7.5 
10. 
15. 
20. 

1.07 
1.60 
2  12 
3.12 
4.07 

66 
95 
131 
192 
251 

79 
115 
157 
230 
301 

86 
125 
170 
250 

:\-2« 

92 
134 
183 
269 
351 

105 
154 
209 
307 
401 

33 


CHAPTER  V 

Method  of  Calculating  Heat  Requirements 

/CHAPTERS  1  and  2  give  the  general  data  that  must  be  known  in 
I  i  calculating  the  heat  requirements  of  any  structure.  Several  rules  and 
formulae  have  been  devised  to  determine  the  amount  of  heat  that 
must  be  supplied  to  maintain  a  room  or  enclosure  at  a  predetermined 
temperature  with  a  known  surrounding  temperature.  Many  of  these 
formulae  were  derived  when  construction,  size  of  window  opening?  etc.,  were 
similar  and  are  not  flexible  enough  to  cover  the  problems  of  today. 

If  the  air  within  an  enclosure  is  maintained  at  a  temperature  higher 
than  that  surrounding,  there  must  be  a  natural  transfer  of  heat  through 
the  enclosing  structure  to  the  air  of  lower  temperatures.  This  transfer  may 
be  to  the  air  outside,  to  any  adjoining  rooms  and  to  air  above  and  below,  if 
these  are  at  lower  temperature  than  that  in  the  room. 

To  heat  the  enclosure  to  and  maintain  it  at  a  predetermined  temper- 
ature, an  equal  amount  of  heat  must  be  supplied  at  the  rate  at  which  it  is 
transferred.  The  most  accurate  method  of  determining  the  quantity 
transferred  is  to  determine  the  hourly  rate  of  heat  transfer  from  the  heated 
enclosure  to  the  surrounding  air.  This  quantity  is  usually  calculated  in 
Rritish  thermal  units  per  hour;  that  is,  on  the  B.t.u.  basis. 

The  total  quantity  transferred  is  made  up  of  four  principal  heat 
requirements. 

The  first  is  the  heat  required  to  warm  to  the  desired  inside  temperature, 
the  air  that  leaks  in  through  the  various  openings  around  the  window  and  door 
perimeters,  etc.,  from  the  outside.  To  calculate  the  heat  units  for  these 
requirements,  the  width  and  lineal  feet  of  the  openings,  and  the  wind  velocity 
against  the  side  of  the  enclosure  where  the  openings  are  located,  must  be 
found,  and  with  these  data  the  air  infiltration  determined.  The  product  of 
the  air  infiltrated  in  cubic  feet  per  hour,  the  density  of  the  air,  its  specific 
heat  and  the  difference  between  the  inside  and  outside  temperatures  will 
give  the  heat  required  per  hour  for  infiltration.  This  subject  is  further 
discussed  in  Chapter  4. 

The  second  is  the  heat  transmitted  through  the  various  materials  of 
which  the  enclosure  is  constructed.  To  calculate  this  requirement,  the  area, 
thickness  and  kind  of  the  various  materials  through  which  this  transfer 
occurs,  and  the  temperature  difference  between  the  air  on  the  two  sides  of 
the  material  must  be  known. 

The  product  of  the  area  of  any  material  in  square  feet,  the  transmission 
coefficient  for  that  material  in  B.t.u.  per  hour,  and  the  difference  between 
the  inside  and  outside  temperatures  will  give  the  heat  transmitted  per  hour 
through  that  material.  The  sum  of  quantities  so  found  for  all  materials 
of  the  structure  is  the  total  loss  of  heat  from  the  enclosure  by  transmission. 

A  desired  maintained  interior  temperature  of  70  deg.  fahr.  and  a  mini- 
mum external  temperature  of  zero  have  been  adopted  in  this  book  as  a 

34 


standard.  All  transmission  coefficients,  therefore,  are  given  in  B.t.u.  per 
hour  per  square  foot  of  surface  for  this  temperature  difference,  with  correc- 
tion factors  for  other  differences. 

A  table  of  these  factors  for  various  materials  used  in  building  con- 
struction will  be  found  on  pages  25  to  30. 

A  third  requirement  enters  into  the  calculation  where  the  heating  is 
not  continuous.  This  may  be  referred  to  as  a  heating  requirement,  or  the 
heat  necessary,  to  raise  the  air  of  the  enclosure  from  its  initial  temperature 
to  the  desired  maintained  temperature.  It  is  evident  that  if  only  sufficient 
heat  is  supplied  to  compensate  for  the  air  infiltration  and  transmission 
requirements,  the  temperature  of  the  enclosure  would  approach  but  not 
reach  the  predetermined  temperature,  unless  additional  heat  units  are 
supplied  for  heating  an  amount  of  air  equivalent  to  the  cubic  contents  of  the 
space  to  be  heated.  To  calculate  this  requirement,  cubic  contents  of  the 
enclosure,  initial  and  final  temperatures  of  the  internal  air,  and  time  desired 
to  raise  the  air  through  this  temperature  range  must  be  determined. 

The  product  of  the  quantity  of  air  in  cubic  feet,  the  density  of  the  air,  its 
specific  heat,  and  the  temperature  difference,  is  the  quantity  of  heat  required 
for  initial  heating  of  the  air.  If  this  quantity  be  then  multiplied  by  the 
reciprocal  of  the  heating-up  period  in  hours,  the  product  will  be  the  quantity 
of  heat  that  must  be  supplied  per  hour  during  the  heating-up  period,  to 
supply  the  heat  absorbed  in  heating  the  air. 

A  fourth  heat  requirement  should  be  included  in  calculations  where 
the  heating  is  not.  continuous,  and  where  large  quantities  of  materials 
such  as  metal,  water,  glass,  etc.,  are  stored  in  the  enclosure  and  must  be 
heated  like  the  air  contents,  from  initial  to  maintained  inside  temperature. 

The  product  of  the  weight  of  such  material  in  pounds,  its  specific  heat 
and  the  desired  temperature  range  is  the  heat  absorbed  by  the  material. 

This  quantity  must  also  be  multiplied  by  the  reciprocal  of  the  heating- 
up  period  in  hours  to  obtain  the  hourly  heat  requirement  during  initial 
heating  to  compensate  for  this  absorption  of  heat.  The  longer  the  heating- 
up  period  selected  the  less  will  be  the  difference  in  the  hourly  requirements 
during  initial  and  maintained  heating. 

Where  large  quantities  of  such  stored  materials  are  taken  into  and  re- 
moved from  the  enclosure  at  intervals  the  heat  absorbed  by  these  materials 
must  be  considered. 

The  sum  of  these  four  requirements  gives  the  total  hourly  rate  at  which 
heat  must  be  supplied  to  maintain  the  enclosure  at  a  predetermined  tem- 
perature, or  to  raise  the  temperature  of  the  enclosure  from  its  initial  to 
predetermined  temperature,  as  the  case  may  be. 

Applying  this  method  of  calculating  heat  loss  requirements,  Figure  5-1 
represents  the  main  floor  of  a  residence  with  warm  basement  and  second 
floor.  Under  these  conditions,  no  ceiling  or  floor  loss  need  be  considered. 

The  quantities  taken  from  the  plan  and  the  basic  data  are  entered  on 
the  Heat-requirement  Computation  Sheet,  Table  5-1. 

The  requirements  are  figured  for  each  exposed  side  as  in  Room  1. 
The  requirement  for  the  north  side  is  12230  B.t.u.,  for  the  east  side  4830 
B.t.u.,  for  the  west  side  1635  B.t.u.  and  the  B.t.u.  required  for  initial  heating 

35 


INCLOSED  L  ,  RABIATO.S  EACH  J         1  <  SEC    »' VE«!f  o  l^F3 

:Er,sR<;L,Li,':,,wT'o0»"i  "«-»  LP'^'^"^n*"-il*S^'"t---H  y''s" 

tOPORILlE  VV.OTM  X          ^OFOHILLEW  "I r J  M.l" 

LENGTH  OF  RADIATOR     J       PERCENT  lv  / 


El  El 

BIS 

REGISTER    143  SO  IN. 


BUILDING  A 


Fig.  5-1.     Plan  of  residence  floor  used  as  basis  for  heat-requirement  computation  sheet,  Table  5-1 

of  the  air  contents  is  632,  making  a  total  maximum  requirement  of  19,327 
B.t.u.  per  hour.  The  heat  supply  for  this  room  should  be  placed  under 
the  north  window. 

The  requirements  in  B.t.u.  per  hour  as  taken  from  the  computation  and 
divided  in  a  similar  manner  are  marked  on  the  plan  for  each  room. 

Another  illustration  of  the  method  of  calculation  is  given  in  the  Heat- 
requirement  Computation  Sheets,  Table  5-2,  for  the  factory  building  shown 
in  Figure  5-2. 

The  calculation  has  been  separately  made  for  the  sections  as  marked 
in  the  figure,  so  that  the  losses  may  be  proportioned  to  the  exposures. 

It  will  be  noted  that  the  correction  factors  are  used  to  change  the 
70-deg.  temperature-difference  coefficients  to  correct  values  for  the  given 
temperature  differences  which  may  vary  due  to  stratification. 

In  section  C,  the  calculations  for  the  north  and  south  walls  with  their 
windows  and  doors  from  the  floor  to  line  a — b  were  made  separately  from 
the  balance  of  the  losses  for  this  section. 

As  the  air  infiltration  from  the  upper  sash  would  not  be  felt  directly  by 
the  operators  in  the  building,  the  infiltration  has  been  calculated  for  only 
the  west  or  side  of  maximum  wind  velocity. 

The  infiltration  factor  for  the  doors  has  been  taken  as  that  of  a  poor 
window,  and  in  calculating  the  window  infiltration  losses  only  the  perimeter 
of  the  ventilating  portion  of  the  window  has  been  considered. 

The  requirements  for  the  various  walls  and  sections  as  taken  from  the 
calculations  are  marked  on  the  drawing  in  their  relative  locations. 

36 


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37 


Sheet  No  
Measured  by  Date  . 

Computed  by  Date  
Checked  by  Date  

Heating  surface 
remarks 

Basic  radiator  eff'y.  238  —  3%  for  length  =  231 
actual  eff'y.  19327  -f-  231  =  84  sq.  ft.  required. 
Installed  one  window  radiator  17  sec.  20-in.  high 
=  85  sq.  ft. 

NORTH  SIDE 

Basic  radiator  eff'y.  260  —2%  for  length  =  255 
actual  eff'y.  6965  +  975  =  7940  -f.  255  =  31 
sq.  ft.  required. 
Installed  one  radiator  2  col.  14  sec.  23-in.  high 
-  32  H  sci.  ft. 
EAST  SIDE 
Basic  radiator  eff'y.  232  —  20%  for  enclosure  — 
3%  for  length  =  180  actual  eff'y. 
11497  +  974  =  12471  4-  180  =  70  sq.  ft.  required. 
Installed  one  radiator  4  col.  18  sec.  22-in.  high 
=  72  sq.  ft. 

Basic  radiator  eff'v.  260  —  3H%  for  length  = 
251  actual  eff'v. 
221)33  -*•  251  =  92  sq.  ft.  required 
Installed  two  radiators  each  2  col.  20  sec,  23-in. 
high  =  46*ssq.  ft. 

Basic  radiator  eff'y.  256  +  4,Mj%  for  length  = 
268  actual  eff'y. 
9295  -i-  268  =  35  sq.  ft.  required 
Installed  two  radiators  each  1  col.  6  sec.  38-in. 
high  =  18  sq.  ft. 

Basic  radiator  eff'y.  266  +  6}4%  for  length  = 
283  actual  eff'y. 
6200  -i-  283  =  22  sq.  ft.  required. 
Installed  two  radiators  each  1  col.  33  sec.  32  in. 
high  =  12.H  sq.  ft. 

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radiator  in  5  units. 

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+  3%  for  room  temp 
24472  ^  383  =  64  sq.  f 
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Basic  radiator  eff'y.  31 
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17472  :-  383  =  46  sq.  f 
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on  Sheet  —  Continued 


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41 


CHAPTER  VI 

Method  of  Computing  and  Selecting 
Heating  Surface 

DETERMINATION  of  the  heating  surface  depends  first  upon  the 
total  hourly  heat  requirements  which  are  assumed  to  have  been 
calculated  as  described  in  the  preceding  chapter.  The  heating 
surface  must  supply  heat  units  to  equal  the  requirements  and  should  be 
of  the  form  that  best  fits  the  conditions  for  the  room  or  enclosure. 

The  method  of  heat  supply  must  first  be  determined — that  is,  whether 
the  heating  surface  is  to  be  direct,  indirect  or  direct-indirect.  The  last  two 
methods  are  used  principally  where  ventilation  must  be  considered  in  addition 
to  the  heating  requirements,  although  the  indirect  method  is  considerably 
used  where  it  is  not  desired  to  have  the  surface  located  in  the  room  to  be  heated. 

Normally,  the  heat  should  be  supplied  at  the  locations  where  the  greatest 
requirements  occur,  and  this  is  generally  at  the  windows,  where,  in  addition 
to  a  high  transmission  requirement,  there  is  the  air  infiltration  requirement 
as  well. 

Rooms  or  enclosures  where  more  than  one  unit  of  radiation  is  to  be 
installed  should  have  the  heating  surface  divided  in  proportion  to  the 
requirements  of  the  spaces  served. 

Heating  surface  placed  under  the  windows  should  not  project  above  the 
sills,  should  be  as  wide  as  the  window  openings,  and  should  also  be  installed 
with  a  2^-inch  space  between  the  wall  and  the  surface,  as  this  distance  gives 
maximum  efficiency  of  heat  emission. 

Direct  heating  surface,  inasmuch  as  it  is  used  in  a  large  majority  of 
installations,  should  be  considered  first.  Residences,  office,  school,  library, 
hospital  and  similar  buildings  usually  have  cast-iron  column  radiation 


Fig.  6-1.     Cast-iron  wall  radiation  on  side  walls  under  windows,  for  heating  a  factory  building 

42 


Fig.  6-2.     Connections  to  a  direct  hot-water  type  radiator  showing  modulation  supply  valve  and 
thermostatically  actuated  return  trap 

together  with  some  cast-iron  wall  radiation.  Factory  and  manufacturing 
buildings  are  usually  heated  by  means  of  wrought-iron  or  steel  pipe  coils  or 
cast-iron  wall  radiation. 

Hot-water  pattern  radiation  is  preferable  for  those  systems  in  which 
modulation  supply  valves  are  to  be  used.  The  supply  valve  should  be  placed 
at  the  upper  inlet  and  the  return  trap  at  the  lower  opening  diagonally 
opposite. 

Good  practice  in  the  use  of  groups  of  wall  radiation  suggests  that  no 
individual  group  exceed  30  ft.  in  length,  as  expansion  and  contraction 
become  an  important  factor  on  longer  groups.  Where  greater  lengths  of  this 
type  of  radiation  must  be  used,  the  supply  connection  should  be  made  at 
top  and  bottom  and  expansion  and  contraction  properly  provided  for. 

Pipe  coil  practice  demands  a  spring  or  mitre  piece  in  the  coil  to  provide 
for  expansion  and  contraction,  and  the  desirable  length  is  limited  to  60  ft. 
not  including  the  mitre  piece.  Coils  should  be  securely  anchored  at  the 
return  header  so  as  to  throw  the  expansion  toward  the  mitre  end,  the  length 
of  which  should  be  not  less  than  one-twelfth  the  coil  length  for  1-in.  pipe 
and  one-tenth  for  1^-in.  or  1^-in.  pipe. 

43 


Fig.   6-3.     Arrangement  of  cast-iron  wall  radiation  on  side  wall  of  a  factory  building 


+  60, 


+  50 


•  +  40 


|430 


•c+20 


^  +10 


\ 


\ 


\ 


-10 


i         9       10       11       12       13       14       15       16       17       18       19      20       21 
Length  of  Radiator  in  Sections 


Fig.  6-4.    Percentage  of  variation  in  heat  emitted  from  cast-iron  heating  surface  per  square  foot  for 
various  numbers  of  sections  as  compared  with  a  standard  10-section  radiator 


The  amount  of  heat  emitted  from  any  given  type  of  direct  heating 
surface  is  usually  stated  in  B.t.u.  per  hour  per  square  foot  of  heating  surface. 
This  heat  is  given  off  in  two  ways,  by  convection  directly  to  the  air  which 
passes  over  the  heated  surface,  and  by  radiation  directly  to  surrounding 
materials  independent  of  that  carried  off  by  the  air.  The  heat  given  off  by 
radiation  does  not  heat  the  air  through  which  it  passes,  but  travels  in  straight 
lines  and  heats  the  objects  upon  which  it  impinges. 

After  selecting  the  type  of  surface  best  suited  for  the  particular  case, 
the  number  of  square  feet  of  heating  surface  required  should  be  deter- 
mined next.  The  total  number  of  heat  units  that  must  be  supplied  per  hour 
divided  by  the  heat  units  emitted  per  hour  per  square  foot  of  heating  surface 
gives  the  required  surface  in  square  feet. 

Table  6-1  will  be  of  assistance  in  determining  the  heat  emitted  by  dif- 
ferent types  of  surface. 

Table  6-1.     B.t.u.  Emitted  per  Hour  per  Square  Foot  of  Heating  Surface* 

Radiators  10  Sections  Long 
Steam  Temperature,  215  deg.  fahr.    Room  Temperature,  70  deg.  fahr. 


Percent 

Number 

Height 

B.t.u. 

B.t.u. 

Total 

convected 

of 

of 

by 

by 

heat  of 

columns 

radia  tor 

convection 

radiation 

B.t.u. 

total  heat 

One 

38  in. 

150 

106 

256 

58.6 

** 

32  in. 

158 

108 

266 

59.4 

*• 

26  in. 

162 

111 

273 

59.4 

u 

23  in. 

160 

119 

279 

57.4 

H 

20  in. 

166 

117 

283 

58.7 

Two 

45  in. 

148 

86 

234 

63. 

** 

38  in. 

148 

92 

240 

62. 

14 

32  in. 

154 

94 

248 

62. 

44 

26  in. 

149 

106 

255 

58. 

"                         1 

23  in. 

151 

109 

260 

58. 

*' 

20  in. 

153 

112 

265 

58. 

Three 

45  in. 

142 

76 

218 

65. 

** 

38  in. 

147 

79 

226 

65. 

H 

32  in. 

158 

75 

233 

68. 

** 

26  in. 

166 

75 

241 

69. 

44 

22  in. 

166 

82 

248 

67. 

44 

18  in. 

162 

92 

254 

64. 

Four 

45  in. 

149 

56 

205 

73. 

44 

38  in. 

150 

60 

210 

71.5 

H 

32  in. 

151 

66 

217 

69.5 

it 

26  in. 

155 

70 

225 

69. 

** 

22  in. 

156 

76 

232 

67. 

U 

18  in. 

151 

87 

238 

63.5 

Wall  radiation 

3  in.  w  ilf 

14  in. 

152 

171 

323 

47. 

M 

22  in. 

154 

156 

310 

49.7 

'* 

29  in. 

138 

157 

295 

48. 

Pipe  co  I 

6-1  J^  in.  pipes 
8-1  Yi  in.     r' 

360 
343 

44 

10-1^  in.     " 

330 

44 

12-1  ^  in.     " 

319 

*  John  R.  Allen.  A.  S.  H.  ff  V.  E.  Journal— January,  1920 

From  Table  6-1  it  will  be  noted  that  low,  narrow  surface  is  most  efficient 
and  that  the  efficiency  decreases  as  the  height  and  width  increase. 


45 


Some  other  factors  and  their  effect  upon  the  efficiency  of  the  radiating 
surface  are  worthy  of  explanation. 

The  preceding  table  is  based  upon  a  radiator  10  sections  long.  As  the 
number  of  sections  decreases,  the  efficiency  increases,  due  to  increase  of  the 
more  efficient  end-section  surface  in  proportion  to  total  heating  surface; 
also  a  short  radiator  emits  proportionally  more  radiant  heat  than  a  longer 
one.  Figure  6-4  shows  the  effect  of  varying  the  number  of  sections,  and 
that  increasing  the  number  of  sections  above  10  has  not  as  much  effect  as 
decreasing  the  number  below  10.  It  will  also  be  noted  that  a  4-section 
radiator  will  give  off  about  10  per  cent  more  heat  per  square  foot  of  surface 
than  one  10  sections  long. 


300 


290 


280 


270 


2CO 


230 


240 


e 

5  220 


3  210 

re 

• 

jL 
I  200 

190 
180 
170 


ICO 


-40         -30         -20         -10  0          +10         +20         +30         +40         +50         +00         +70         +80 

Percentage  Variation  in  Heat  Emission 

Fig.  6-5.     Percentage  variation  in  heat  emitted  from  heating  surface  due  to  varying  the  steam 
temperature  from  215  deg.  fahr..  room  temperature  70  deg.  fahr. 

46 


Where  215  deg.  fahr.  is  considered  as  the  standard  temperature  of 
steam  in  the  heating  surface,  the  effect  upon  the  heat  emission  of  the 
surface  due  to  varying  this  temperature  is  shown  in  Figure  6-5.  The 
percentage  variation  can  be  read  directly  from  the  curve. 

Example:  If  steam  at  a  temperature  of  230  deg.  fahr.  is  supplied  to 
the  radiator,  the  heat  emission  will  be  increased  12  per  cent  over  one 
supplied  with  steam  at  215  deg.  fahr. 


4-20 


I 

E 

§   ° 


I 

£-10 


-20. 


10 


50 


60  70  80  90 

Room  or  Surrounding  Temperature -Deo.  Fahr. 


100 


110 


Fig.  6-6.     Percentage  variation  in  heat  emitted  from  heating  surface  due  to 
varying  the  room  temperature  from  70  deg.  fahr. 

The  surrounding  or  room  temperature  is  taken  at  70  deg.  fahr.  as  a 
standard.  The  effect  upon  the  heat  emitted  from  heating  surface,  due  to 
varying  this  temperature,  is  shown  graphically  in  Figure  6-6.  From  the 
curve  it  will  be  observed  that,  for  instance,  a  radiator  in  a  room  temperature 
of  60  deg.  fahr.  will  emit  6  per  cent  more  heat  than  the  same  radiator  in  a 
room  temperature  of  70  deg.  fahr. 

The  effect  on  heat  emission  due  to  variation  in  steam  temperature  is 
much  greater  than  an  equal  temperature  variation  in  the  surrounding  or 
room  temperature. 

The  following  example  will  illustrate  the  use  of  the  curves  in  Figures 
6-4,  6-5  and  6-6  for  determining  the  heat  emission  under  given  conditions; 
it  is  desired  to  know  the  B.t.u.  emitted  per  hour  per  square  foot  of  heating 
surface  of  a  standard  cast-iron  radiator,  two  columns  wide,  38  in.  high, 
and  six  sections  long  when  supplied  with  steam  at  240  deg.  fahr.  and  located 
in  a  room  heated  to  80  deg.  fahr. 

Referring  to  Table  6-1,  a  similar  radiator  except  that  it  is  10  sections 
long,  gives  off  240  B.t.u.  per  hr.  per  sq.  ft.,  with  steam  at  215  deg.  fahr. 
in  room  temperature  70  deg.  fahr.  A  radiator  six  sections  long  is  4.5  per 
cent,  more  efficient  (Figure  6-4),  when  supplied  with  steam  at  240  deg. 

47 


i 

t2J"        ,                       « 

/           I2*" 

ft  ,'~      hf         m 

// 

V                                                                                                                          ^/ 

//    /                       i  

1 

x-ATN                                  ^ 

X-7A-N 

0                       1'      rf\^ 

: 

/  v  y\ 

" 

(  C 

A 

; 

—  y_ 

\ 

•         { 

^            '• 

21" 

= 

X 

2$" 

X 

2! 

| 

^ 

^ 

| 

^ 

% 

g 

^ 

| 

" 

| 

• 

- 
' 

: 

(! 

h 

yv 

,    1        I 

{ 

y/ 

•31 

T             Ic 

-L                 /A 

=Q 

^/^//^//^/^/^^                    '^//////^/////^/^^^                   e///y//////z#/////^^^ 

Fig.  6-7                                                         Fig.  6-8                                                       Fig.  6-9 

^                                                                                                        'K_,^    K_O—  ^ 

x/// 

'///////////A      I                      i 

I 

iy. 

rS^ 

0 

— 

T 

r 

^ 

o^ 

.- 

Shield 

1 

*\ 

''•: 

1 

1 

i 

^   r21" 

2J" 

1 

„ 

•i 

2J 

^ 

H 

v 

-11 

f- 

'  :  i 

49' 

| 

y/ 

| 

C 

; 

\  1 

2 

T 

' 

""i 
i^J    / 

| 

^./~\A                i  <V     V>      1   , 

1 

i/'^i 

/; 

'/////^//ffi//////,             „/,///,„„/,/////////////                       y///////////////////////////// 

Fig.  6-10                                                   Fig.  6-11                                                      Fig.  6-12 

1 

'///////////////////////^^^^ 

^ 

Length  of  all  outlets  O  =  length  of  radiator 
y 
Length  of  all  inlets  I  =  length  of  radiator 

', 

'/ 

| 

0                  tl 

Width  of  all  outlets  O  =  width  of  radiator  or  as 

J 

\AAAAAAy 

given  in  table 

_I  a                        p|an                   <  a  v                Screens  or  grilles  have  41  per  cent  free  area 

i                    r      i 

Fig.  6-13 

Enclosures  for  radiators 
48 


fahr.,  the  efficiency  is  increased  20  per  cent  (Figure  6-5),  and  if  located  in  a 
room  heated  to  80  deg.  fahr.  there  is  a  decrease  in  efficiency  of  6  per  cent 
(Figure  6-6).  The  heat  emission  of  the  radiator  required  would  be  240  x 
1.045  x  1.20  x  0.94=283  B.t.u.  per  hr.  per  sq.  ft.  of  radiating  surface. 

Painting  a  radiator  influences  only  the  heat  emitted  by  radiation,  the  con- 
vection factor  remaining  practically  unchanged.  As  paint  affects  the  surface 
only,  the  number  of  coats  makes  little  difference.  It  seems  to  depend  on  the 
last  coat  applied  and  when  made  of  flake  metal  the  result  is  more  marked. 

Direct  radiators  are  sometimes  set  behind  grilles  or  screens,  in  window 
enclosures  or  wall  recesses,  all  of  which  greatly  decrease  the  efficiency  of 
the  radiation. 

Tests  by  Professor  Hrabbee,  as  reported  by  George  Stumpf,  Heating 
and  Ventilating  Magazine,  May,  1914,  show  that  a  radiator  in  an  enclosure 
is  most  efficient  when  located  with  2}/£  inches  between  the  wall  and  radiator 
and  between  the  inside  of  the  enclosure  and  the  radiator.  Abstracts  from 
these  tests  follow. 

The  inlet  and  outlet  openings  of  any  form  of  enclosure  should  extend  at 
least  the  entire  length  of  the  radiator.  The  width  of  the  outlet  is  usually 
made  that  of  the  radiator.  Tests  show  little  gain  in  efficiency  for  wider 
outlets,  but  a  decrease  of  about  5  per  cent  for  each  inch  narrower  than 
that  of  the  radiator. 

The  outlets  and  inlets  in  Tables  6-7  to  6-13  are  the  full  length  of  the 
radiators.  The  width  of  outlet  0  is  the  width  of  the  radiator  except  in  Table 
6-4,  where  it  is  as  given.  The  width  of  inlet  I  is  as  stated  in  the  tables. 


Fig.  6-H.     An  enclosed  radiator  having  grilles  or  screens  on  front  and  top  of  enclosure.     The 
modulation  supply  valve  control  is  shown  on  top  of  enclosure 

40 


Both  openings  are  covered  with  screen  of  44  per  cent  free  area. 

The  design  of  the  screen  or  grille  has  no  effect  prpvided  the  free  area 
is  not  changed. 

Figure  6-7  shows  a  form  of  enclosure  frequently  used. 

Table  6-2.    Decrease  in  Radiator  Efficiency  with  Form  of  Enclosure  Shown  in  Fig.  6-7 


Radiator  width 

Radiator  height 

Width  of  I 

Decrease  in  efficiency 

Two-column 

42  in.  and  over 

9  in. 

15% 

«         n 

Under  42  in. 

9  in. 

20% 

.<         " 

Under  42  in. 

5  in. 

25% 

Three-column 

42  in.  and  over 

9  in. 

15% 

32  in.  to  38  in. 

9  in. 

15% 

..           .. 

32  in.  to  38  in. 

7  in. 

20% 

.. 

26  in.  and  under 

9  in. 

20% 

41                            .. 

26  in.  and  under 

5  in. 

25% 

If  the  width  of  inlet  is  made  equal  to  the  free  area  and  not  screened,  the 
efficiency  reduction  will  remain  as  above. 

Another  form  of  enclosure,  Figure  6-8,  gives  the  effect  upon  the  radi- 
ation efficiency  as  shown  in  Table  6-3. 

Table  6-3.     Decrease  in  Radiator  Efficiency  with  Form  of  Enclosure  Shown  in  Fig.  6-8 


Radiator  width 

Radiator  height 

Width  of  O 

Width  of  I 

Decrease  in  efficiency 

Two-column 

42  in.  and  over 
32  in.  to  38  in. 
32  in.  to  38  in. 
26  in.  and  under 

8  in. 
9  in. 
Tin. 
6  in. 

8  in. 
9  in. 
Tin. 
6  in. 

20% 
20% 
25% 
33% 

Three-column 

26  in.  and  over 
26  in.  and  over 

9  in. 
6  in. 

9  in. 
6  in. 

20% 
25% 

Enclosure  of  the  form  shown  in  Figure  6-9  is  sometimes  used  and  by 
test  gives  the  following  effect: 

Table  6-4.    Decrease  in  Radiator  Efficiency  with  Form  of  Enclosure  Shown  in  Fig.  6-9 


Perforated  screen  full  front  of  enclosure  only — decrease  in  efficiency 20% 

Same  screen  with  deflector —  •    •   15% 

If  an  outlet  O  is  provided  in  addition  to  front  screen  and  made  equal  to 
width  and  length  of  the  radiator,  the  efficiency  decreases  only  10  per  cent. 

Sometimes  it  is  desirable  to  set  the  radiators  in  wall  recesses,  as  shown 
in  Figures  6-10  and  6-13  which  causes  a  decrease  in  efficiency  as  follows: 

Table  6-5.    Decrease  in  Radiator  Efficiency  Due  to  Wall  Recess  Fig.  6-10 


When  0  =  1  V-t  inches — decrease  in  efficiency 11% 

"     0  =  3    '      "  "         "         "         7.3% 

"     0  =  4          "  "         "  6% 

The  distance  a  has  little  or  no  effect,  and  therefore  need  only  be 
sufficient  for  connections  to  the  radiator. 

A  shield  in  front  of  a  radiator  as  shown  in  Figure  6-11  increases  the 
radiator  efficiency  as  follows: 


50 


Fig.  6-15.     An  enclosed  radiator  in  a  window  seat,  with  grilles  of  rattan  cane.    The  modulation 
supply  valve  control  is  placed  on  the  window  seat 

Table  6-6.     Increase  in  Radiator  Efficiency  by  Use  of  a  Shield  Fig.  6-11 


Height  of  shield,  H 52  in.  52  in.  52  in. 

Width  of  open  slot,  1 6J^  in.  9  in.  12  in. 

Increase  in  efficiency 2.2%  6.3%  12.5% 


72  in. 
12  in. 
13% 


Another  form  of  enclosure,  shown  in  Figure  6-12,  by  test  gives  the  fol- 
low ing  effect  upon  the  radiator  efficiency: 

Table  6-7.    Decrease  in  Radiator  Efficiency  with  Form  of  Enclosure  Shown  in  Fig.  6-12 

Width  I 8  in.  6  in.  5  in.  4  in.  3  in. 

Decrease  in  efficiency 10%  15%  20%  25%  33% 


Table  6-8.     Comparative  B.t.u.   Transmission  and  Cost  of  Cast-iron  Heating  Surface 
Based  on  3-column  30-in.  radiation  as  1.00 


Rad. 

Relative  cost  of  radiator  per  sq.  ft. 

B.t.u.  given  off  per  sq.  ft. 

Relative  cost  based  on  heating 
efficiency 

height 

1 

2 

3 

4 

1 

2 

3 

4 

1 

2 

3 

4 

Column 

Columns 

Columns 

Columns 

Col. 

Col's 

Col's 

Col's 

Column 

Columns 

Columns 

Columns 

18' 

1.43 

1.43 

254 

238 

1.27 

1.36 

20' 

1.49 

1.43 

283 

265 

1.19 

1  22 

22' 

1.28 

1.28 

248 

232 

1.17 

1   25 

23' 

1.38 

1.31 

279 

260 

1.10 

1.14 

26' 

1  30 

1.25 

1.18 

1.18 

273 

255 

241 

225 

1  08 

1.11 

1.10 

1.18 

32' 

1.18 

1.13 

1.08 

1  08 

266 

218 

233 

217 

1.01 

1.03 

1  .  04 

1.12 

38' 

1.09 

1.04 

1.00 

1.00 

256 

240 

226 

210 

.96 

.95 

1.00 

1.08 

45' 

l()t 

1.00 

1.00 

1'.'!  t 

218 

205 

1.01 

l.M 

1.11 

These  tabli-*  ;irr  IKIM-I!  on  investigations  of  10-section  radiators 

For  Radiators  under  6-section,  the  B.t.u.  per  sq.  ft.  increases  rapidly  and  the  tables  cannot  be  used 
rith  accuracy.    Above  6-section  the  error  is  small 

51 


Table  6-8  will  be  of  interest  as  it  compares  the  relative  costs  of  cast- 
iron  heating  surface  of  different  heights  and  number  of  columns  where  the 
efficiency  of  the  surface  is  taken  into  consideration. 

As  an  example,  compare  the  relative  cost  of  3-column  38-in.  with 
single-column  23-in.  surface.  The  3-column  surface  cost  is  figured  as  1.00 
and  it  emits  226  B.t.u.  per  sq.  ft.  per  hr.  The  single-column  radiator 
cost  is  1.36  but  it  emits  279  B.t.u.  per  sq.  ft.  per  hr.  Although  the  actual 
cost  per  square  foot  for  the  single-column  radiator  is  36  per  cent  more  than 
for  the  3-column,  the  1 -column  radiator  is  23  per  cent  more  efficient  in 
heat  emission.  If  this  increase  in  heating  efficiency  is  considered,  the  cost 
of  the  single-column  radiation  is  only  10  per  cent  more. 

Indirect  heating  surface  generally  refers  to  that  located  below  and 
outside  of  the  room  to  be  heated.  (See  Figure  6-16.)  The  heat  is  delivered  to 
the  room  by  a  system  of  ducts  that  convey  fresh  air  from  outside.  The  air 
passes  over  the  surface,  is  heated  and  then  discharged  into  the  room  through 
register  faces  located  in  the  room  floor  or  wall.  This  method  of  heating  is 


Dry  Return 


'  Air  Line  into  Top  of 
Dry  Return. K"when  Dry 
Return  is  over  10'  0" 

"  WEBSTER  RETURN  TRAP  Distant  | 

Place  same  above  highest 
Point  ot  Dry  Return 


O) Supply  Main 


Indirect  Radiator 
Parts  of  Casing  removed 


Full  size  Nipple  to  outside  of  Radiator 
Casing,  than  a  full  size  Ell  and  Nipple 
connecting  to  a  reducing  Ell  Not  kss  .„  30" 


12"x  12"  Sliding  Door  at 
Bottom  of  Casing 


Union  above  Water  Line  of  Boiler 
Water  Line  of  Boiler 


Connect  into  Wet  Return  Main 


Special  Swing  Check  Valve 
This  Connection  to  be  on  the  same  Centre  as  Wet  Return 


Fresh  Air 


Quadrant  Damper 
Clean  Out  Door 


Wet  Return  near  Floor 


Floor  Line 


Fig.  6-16.     Connections  to  an  indirect  radiator 
52 


called  fresh  air  indirect,  as  a  constant  supply  of  fresh  heated  air  is  delivered 
into  the  room.  The  cold  air  duct  is  sometimes  so  arranged  that  outside  air  may 
be  closed  off  and  air  taken  from  the  basement  in  extreme  cold  weather. 

Where  the  air  supply  is  taken  from  the  room,  passed  over  the  heating 
surface  and  then  discharged  into  the  room  again,  the  method  is  known 
as  recirculatitiy  indirect. 

In  either  system  no  heating  surface  is  located  in  the  room  to  be  heated. 

The  indirect  method  of  heating  is  most  used  in  the  principal  rooms  of 
residences,  clubs,  churches  and  similar  types  of  buildings,  and  is  much 
more  expensive  to  install  and  to  operate  than  is  the  direct  system. 

All  rooms  heated  by  the  fresh  air  indirect  system  must  be  provided 
with  vents  for  the  escape  of  the  air  replaced  by  that  delivered  by  the  "  indirect 
stack,"  as  this  type  of  heating  surface  is  often  called. 

Many  variable  factors,  each  of  prime  importance,  enter  into  an  accurate 
calculation  of  the  proper  proportions  of  a  system  of  this  type.  These  vari- 
ables include  velocity  and  direction  of  the  wind,  frictional  resistance  to  the 
air  flow  in  the  ducts,  and  the  loss  of  heat  due  to  transmission  through  the 
walls  of  hot-air  ducts. 

Each  manufacturer  of  heating  surface  for  this  system  has  his  own 
special  design,  which  is  usually  sold  by  catalogue  ratings  in  square  feet  of 
surface.  Reliable  data  as  to  the  free  area  between  sections  and  the  heating 
effect  under  the  variable  conditions  of  steam  and  air  temperatures  at  various 
air  velocities  are  unfortunately  not  available  for  each  make  of  heating 
surface  used  in  this  method  of  heating.  Proper  values  are  very  difficult  to 
assign  to  the  variable  factors,  and  the  several  rules  for  determining  the 
proper  proportions  of  such  a  system  are  all  based  upon  some  standard 
conditions  and  assumptions. 

The  general  principle  of  an  indirect  system  is  the  delivery  of  air  to  the 
room  at  a  temperature  higher  than  that  of  the  room,  and  in  such  volume 
that  in  cooling  to  room  temperature,  sufficient  heat  units  are  given  up  to 
replace  those  required  for  transmission,  infiltration  and  other  requirements. 

The  requirements  for  this  method  of  heating  are  usually  computed  in 
the  following  way: 

First:  Calculate  the  total  heat  requirements  in  B.t.u.  per  hour  for  the 
room  to  be  heated  as  described  in  Chapter  5. 

Second:  Determine  the  height  of  the  column  of  heated  air;  that  is,  the 
distance  from  center  of  indirect  stack  to  center  of  the  room  register. 

Third:  Assume  the  temperature  of  the  air  entering  the  room.  This  is 
usually  taken  about  120  deg.  fahr.  where  air  enters  the  radiator  at  zero  and 
the  radiator  is  supplied  with  steam  at  atmospheric  pressure  or  slightly  above. 

Fourth:  Determine  the  velocity  of  air  due  to  difference  in  densities 
between  heated  and  outside  air  for  columns  of  equal  height. 

Fifth:  Ascertain  from  the  manufacturer  of  the  selected  type  of  heating 
surface  the  velocity  at  which  air  must  pass  through  the  surface  to  produce 
the  final  required  temperature,  when  the  surface  is  supplied  with  steam  at  a 
predetermined  temperature  and  air  enters  the  heating  stack  at  the  minimum 
outside  temperature.  Ascertain  also  the  temperature  of  the  air  on  which 
this  performance  is  based,  the  free  area  between  the  sections,  and  the 

53 


number  of  square  feet  of  heating  surface  per  section. 

The  amount  of  heating  surface  may  then  be  determined  as  follows: 

H  =  total  B.t.u.  losses  per  hour  for  the  room. 

t,  =  temperature  of  air  entering  the  room. 

t«  =  temperature  of  air  in  room  (room  temperature)  . 

t,  =  temperature  of  air  on  which  heating  surface  performance  is  based. 

d  =  density  of  air  at  temperature  fc. 

v  =  performance  velocity  of  air  in  feet  per  minute. 

a  =  free  area  per  section  of  heating  surface  in  square  feet. 

TT 

'        .    .-„  =  pounds  of  air  required  per  minute  =  P 

(^ti-t-jj     OU 


where  0.2375  is  the  specific  heat  of  the  air. 
p 
T  =  cubic  feet  of  air  per  minute  at  t,. 

p 

-T  -r-  av  =  number  of  sections  of  heating  surface  required  from  which 

the  square  feet  of  heating  surface  can  be  determined. 
The  sizes  of  the  ducts  or  flues  for  conveying  the  air  to  and  from  the 
heating  surface  are  dependent  upon  the  velocity  of  the  air  due  to  the 
unbalanced  air  column.     This  velocity  may  be  determined  theoretically 
from  the  formula: 

/ 
in  which 


v  =  velocity  in  feet  per  minute. 

h  =  height   of  warm  air  column  in   feet   or  distance   from   center  of 

heating  surface  to  center  of  register. 
t  =  average  temperature  of  air  in  column. 
to  =  average  temperature  of  outside  air. 

To  allow  for  friction  in  ducts,  through  heating  surface,  register  face 
and  elsewhere,  velocities  of  one-third  of  the  theoretical  may  be  assumed. 
The  area  of  the  hot-air  duct  may  be  determined  as  follows  : 

.  144  P 

Area  in  square  inches  =  — 

d  v 

in  which 

P  =  pounds  of  air  required  per  minute. 

d  =  density  of  air  at  average  temperature  in  hot-air  duct. 

v  =  velocity  in  feet  per  minute  in  duct. 

The  register  can  have  a  free  area  equal  to  the  area  of  the  hot-air 
duct  where  velocity  in  hot-air  duct  is  not  in  excess  of  300  ft.  per  min.  For 
higher  velocities  the  register  area  should  be  increased.  The  area  of  the  cold- 
air  duct  can  be  determined  in  a  manner  similar  to  the  hot-air  duct  area, 
using  density  of  the  air  at  the  cold  inlet  temperature. 

Direct  -indirect  heating  surface,  as  the  name  implies,  consists  of  radiators 
arranged  so  that  a  portion  of  each  serves  on  the  indirect  principle  and  the 
remainder  as  a  direct  radiator;  the  entire  surface,  however,  is  located  in  the 

54 


room  to  be  heated.  This  combination  is  accomplished  by  providing  a  direct 
radiator  and  installing  a  metal  box  base  under  some  of  the  sections.  Cold 
fresh  air  is  taken  from  the  outside  of  the  building  directly  through  the  wall 
and  connected  to  this  box  base.  The  fresh  air  passes  up  through  its  portion  of 
the  surface  into  the  room.  The  balance  of  the  surface  acts  as  plain  direct 
heating  surface. 

This  method  of  heating  has  come  into  quite  general  use  in  recent  years 
in  some  localities  where  the  state  ventilation  laws  for  public  buildings  specify 
either  the  quantity  of  air  to  be  supplied  per  minute  per  person,  or  the  number 
of  square  inches  of  fresh-air  inlet  duct  per  person.  The  latter  requirement 
can  be  met  with  this  type  of  heating  surface. 

The  size  of  the  opening  in  the  wall  or  the  wall  box  determines  the  size 
of  the  box  base,  and  the  number  of  sections  of  the  radiator  enclosed  by  the 
box  base  are  to  be  considered  as  available  only  for  heating  the  incoming  air. 

Sufficient  additional  direct  heating  surface  must  be  provided,  either  by 
adding  sections  to  the  radiator,  extending  same  outside  of  the  box  base  on 
either  end,  or  by  installing  separate  units  for  supplying  the  heat  necessary 
for  requirements  of  the  wall,  glass  and  infiltration,  as  already  mentioned. 

Vent  flues  must  be  extended  from  all  rooms  heated  and  ventilated  by 
this  method. 

In  order  to  obtain  desired  air  movement  and  prevent  back  draft  in  flues, 
they  must  have  aspirating  radiation  or  rotary  type  ventilators. 

The  radiation  best  suited  for  direct-indirect  surface  is  that  with  high 
and  wide  sections.  One  manufacturer  of  the  most  modern  devices  for  this 
type  of  system  states  the  size  of  the  ventilating  base,  together  with  its  capac- 
ity, fresh-air  inlet  area  and  amount  of  radiating  surface  to  be  enclosed,  as 
given  in  Table  6-9. 

Table  6-9.     Data  for  Direct-indirect  Heating  Surface  Offered  by  One 
Manufacturer.     Not  Standard  for  Other  Similar  Equipment 

Capacity  in  Area  of  fresh 

Size  of  wall  box  cu.  ft.  per  min.  air  opening  Heating  surface 


8   in.  x  20  in. 

180 

120  sq.  in. 

50  sq.  ft. 

8   in.  x  21  in. 

240 

in 

50 

8   in.  x  30  in. 

300 

180 

60 

10H  in-  x  20  in. 

270 

160 

50 

10J^  in.  x  24  in. 

330 

192 

60 

10J/6  in.  x  30  in. 

420 

240 

60 

As  an  example  of  selecting  and  computing  heating  surfaces,  refer  to  the 
heat  requirements  as  shown  on  Pages  38-39  for  the  various  rooms  in  Figure 
5-1,  Page  36,  and  assume  that  steam  will  be  used  at  215  deg.  fahr.,  or  1-lb. 
per  sq.  in.  pressure. 

Room  3  requires  a  total  of  22933  B.t.u.  per  hr.  and  is  to  be  heated 
by  means  of  direct  radiation.  The  window  sills  are  24  in.  high.  There- 
fore, 23-in.  high  radiators  should  be  installed.  For  a  room  of  this  size,  it 
appears  that  2-column  radiation  should  give  sufficient  surface.  The 
B.t.u.  emitted  by  2-column,  23-in.  high  radiation  is  given  in  Table  6-1 

55 


Table  6-10.     Surface  in  Square  Feet  of  One  to  Twelve  l^-inch  Pipe  Coil, 

1  to  100  Feet  Long 

(For  other  sizes  of  pipe,  see  note  at  bottom  of  next  page.) 


Length 
of  coil 
in  feet 

Number  of  \Y\ 

'  pipes 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

Square 

feet  of  heating  surface 

1 

0.43 

0.86 

1.29 

1. 

72   2 

15   2. 

58   3. 

01   3. 

44   3. 

87   4.30 

4. 

73   5.16 

2 

1 

o 

3 

3 

4 

5 

6 

7 

8 

9 

9 

10 

3 

1 

3 

4 

5 

6 

8 

9 

10 

12 

13 

14 

15 

4 

2 

3 

5 

7 

9 

10 

12 

14 

15 

17 

19 

21 

5 

2 

4 

6 

9 

11 

13 

15 

17 

19 

22 

24 

26 

6 

3 

5 

8 

10 

13 

15 

18 

21 

23 

26 

28 

31 

7 

3 

6 

9 

12 

14 

18 

21 

24 

27 

30 

33 

36 

8 

3 

7 

10 

14 

17 

21 

24 

28 

31 

34 

38 

41 

9 

4 

8 

12 

15 

19 

23 

27 

31 

35 

39 

43 

46 

10 

4 

9 

13 

17 

22 

26 

30 

34 

39 

43 

47 

52 

11 

5 

9 

14 

19 

24 

28 

33 

38 

43 

47 

52 

57 

12 

5 

10 

15 

21 

26 

31 

36 

41 

46 

52 

57 

62 

13 

6 

11 

17 

22 

28 

34 

39 

45 

50 

56 

61 

67 

14 

6 

12 

18 

24 

30 

36 

42 

48 

54 

60 

66 

72 

15 

6 

13 

19 

26 

32 

39 

45 

52 

58 

65 

71 

77 

16 

7 

14 

21 

28 

34 

41 

48 

55 

62 

69 

76 

83 

17 

7 

15 

22 

29 

37 

44 

51 

58 

66 

73 

80 

88 

18 

8 

15 

23 

31 

39 

46 

54 

62 

70 

77 

85 

93 

19 

8 

16 

25 

33 

41 

49 

57 

65 

74 

82 

90 

98 

20 

9 

17 

26 

34 

43 

52 

60 

69 

77 

86 

95 

103 

21 

9 

18 

27 

36 

45 

54 

63 

72 

81 

90 

99 

108 

22 

9 

19 

28 

38 

47 

57 

66 

76 

85 

95 

104 

114 

23 

10 

20 

30 

40 

49 

59 

69 

79 

89 

99 

109 

119 

24 

10 

21 

31 

41 

52 

62 

72 

83 

93 

103 

114 

124 

25 

11 

22 

32 

43 

54 

65 

75 

86 

97 

108 

118 

129 

26 

11 

22 

34 

45 

56 

67 

78 

89 

101 

112 

123 

134 

27 

12 

23 

35 

46 

58 

70 

81 

93 

104 

116 

128 

139 

28 

12 

24 

36 

48 

60 

72 

84 

96 

108 

120 

132 

144 

29 

12 

25 

37 

50 

62 

75 

87 

100 

112 

125 

137 

150 

30 

13 

26 

39 

52 

65 

77 

90 

103 

116 

129 

142 

155 

31 

13 

27 

40 

53 

67 

80 

93 

107 

120 

133 

147 

160 

32 

14 

28 

41 

55 

69 

83 

96 

110 

124 

138 

151 

165 

33 

14 

28 

43 

57 

71 

85 

99 

114 

128 

142 

156 

170 

34 

15 

29 

44 

58 

73 

88 

102 

117 

132 

146 

161 

175 

35 

15 

30 

45 

60 

75 

90 

105 

120 

135 

151 

166 

181 

36 

15 

31 

46 

62 

77 

93 

108 

124 

139 

155 

170 

186 

37 

16 

32 

48 

64 

80 

95 

111 

127 

143 

159 

175 

191 

38 

16 

33 

49 

65 

82 

98 

114 

131 

147 

163 

180 

196 

39 

17 

34 

50 

67 

84 

101 

117 

134 

151 

168 

184 

201 

40 

17 

34 

52 

69 

86 

103 

120 

138 

155 

172 

189 

206 

41 

18 

35 

53 

71 

88 

106 

123 

141 

159 

176 

194 

212 

42 

18 

36 

54 

72 

90 

108 

126 

144 

163 

181 

199 

217 

43 

18 

37 

55 

74 

92 

111 

129 

148 

166 

185 

203 

222 

44 

19 

38 

57 

76 

95 

114 

132 

151 

170 

189 

208 

227 

45 

19 

39 

58 

77 

97 

116 

135 

155 

174 

194 

213 

232 

46 

20 

40 

59 

79 

99 

119 

138 

158 

178 

198 

218 

237 

47 

20 

40 

61 

81 

101 

121 

141 

162 

182 

202 

222 

243 

48 

21 

41 

62 

83 

103 

124 

144 

165 

186 

206 

227 

248 

49 

21 

42 

63 

84 

105 

126 

147 

169 

190 

211 

232 

253 

50 

22 

43 

65 

86 

108 

129 

151 

172 

194 

215 

237 

258 

56 


Table  6-10.     Surface  in  Square  Feet  of  One  to  Twelve  l^-inch  Pipe  Coil, 
1  to  100  Feet  Long — Continued 


Length 
of  coil 
in  feet 

Number  of  1  '  ,  "  pipes 

1 

2 

3 

4 

s 

6 

7 

8 

9 

10 

11 

12 

Square  fe< 

•t  of  heating 

surface 

.->! 

•2-2 

11 

66 

88 

110 

132 

154 

175 

197 

219 

241 

263 

52 

22 

45 

67 

89 

112 

134 

157 

179 

201 

224 

246 

268 

53 

23 

46 

68 

91 

114 

137 

160 

182 

205 

228 

251 

273 

54 

23 

46 

70 

93 

116 

139 

163 

186 

209 

232 

255 

279 

55 

24 

47 

71 

95 

118 

142 

166 

189 

213 

237 

260 

284 

56 

24 

48 

72 

96 

120 

144 

169 

193 

217 

241 

265 

289 

57 

25 

49 

74 

98 

123 

147 

172 

196 

221 

245 

270 

294 

58 

25 

50 

75  . 

100 

125 

150 

175 

200 

224 

249 

274 

299 

59 

25 

51 

76 

101 

127 

152 

178 

203 

228 

254 

279 

304 

60 

26 

52 

77 

103 

129 

155 

181 

206 

232 

258 

284 

310 

61 

26 

52 

79 

105 

131 

157 

184 

210 

236 

262 

289 

315 

62 

27 

53 

80 

107 

133 

160 

187 

213 

240 

267 

293 

320 

63 

27 

54 

81 

108 

135 

163 

190 

217 

244 

271 

298 

325 

64 

28 

55 

83 

110 

138 

165 

193 

220 

248 

275 

303 

330 

65 

28 

56 

84 

112 

140 

168 

196 

224 

252 

280 

307 

335 

66 

28 

57 

85 

114 

142 

170 

199 

227 

255 

284 

312 

341 

67 

29 

58 

86 

115 

144 

173 

202 

230 

259 

288 

317 

346 

68 

29 

58 

88 

117 

146 

175 

205 

234 

263 

292 

322 

351 

69 

30 

59 

89 

119 

148 

178 

208 

237 

267 

297 

326 

356 

70 

30 

60 

90 

120 

151 

181 

211 

241 

271 

301 

331 

361 

71 

31 

61 

92 

122 

153 

183 

214 

244 

275 

305 

336 

366 

72 

31 

62 

93 

124 

155 

186 

217 

248 

279 

310 

341 

372 

73 

31 

63 

94 

126 

157 

188 

220 

251 

283 

314 

345 

377 

74 

32 

64 

95 

127 

159 

191 

223 

255 

286 

318 

350 

382 

75 

32 

65 

97 

129 

161 

194 

226 

258 

290 

323 

355 

387 

76 

33 

65 

98 

131 

163 

196 

229 

261 

294 

327 

359 

392 

77 

33 

66 

99 

132 

166 

199 

232 

265 

298 

331 

364 

397 

78 

34 

67 

101 

134 

168 

201 

235 

268 

302 

335 

369 

402 

79 

34 

68 

102 

136 

170 

204 

238 

272 

306 

340 

374 

408 

80 

34 

69 

103 

138 

172 

206 

241 

275 

310 

344 

378 

413 

81 

35 

70 

104 

139 

174 

209 

244 

279 

313 

348 

383 

418 

82 

35 

71 

106 

141 

176 

212 

247 

282 

317 

353 

388 

423 

83 

36 

71 

107 

143 

178 

214 

250 

286 

321 

357 

393 

428 

84 

36 

72 

108 

144 

181 

217 

253 

289 

325 

361 

397 

433 

85 

37 

73 

110 

146 

183 

219 

256 

292 

329 

366 

402 

439 

86 

37 

74 

111 

148 

185 

ooo 

259 

296 

333 

370 

407 

444 

87 

37 

75 

112 

150 

187 

224 

262 

299 

337 

374 

412 

449 

88 

38 

76 

114 

151 

189 

227 

265 

303 

341 

378 

416 

454 

89 

38 

77 

115 

153 

191 

230 

268 

306 

344 

383 

421 

459 

90 

39 

77 

116 

155 

194 

232 

271 

310 

348 

387 

426 

464 

91 

39 

78 

117 

157 

196 

235 

274 

313 

352 

391 

430 

470 

92 

40 

79 

119 

158 

198 

287 

277 

316 

356 

396 

435 

475 

93 

40 

80 

120 

160 

200 

L'K) 

280 

320 

360 

400 

440 

480 

94 

40 

81 

121 

162 

202 

243 

283 

323 

364 

404 

445 

485 

95 

41 

«L> 

123 

163 

204 

215 

286 

327 

368 

409 

449 

490 

96 

41 

83 

124 

165 

206 

2IK 

289 

330 

372 

413 

454 

495 

97 

42 

83 

125 

167 

209 

250 

090 

:?:!  i 

:i:r> 

117 

459 

501 

98 

42 

84 

126 

169 

211 

2.>:5 

2<)H 

337 

379 

421 

464 

506 

99 

i:: 

85 

12» 

17(1 

213 

255 

298 

341 

383 

426 

468 

511 

100 

43 

86 

129 

172 

215 

258 

301 

344 

387 

l.'.n 

m 

516 

Note:  For  all  practical  purposes,  figure  1-3  sq.  ft.  of  outside  surface  per  lineal  foot  of  1-in.  pipe;  and  1-2  sq.  ft.  for  1  1-2  in.  pipe 

57 


as  260  B.t.u.  per  hr.  per  sq.  ft.  of  surface.  As  these  radiators  will  be  20 
sections  long  instead  of  the  standard  10,  on  which  the  above  efficiency  was 
based,  the  efficiency,  or  B.t.u.  emitted  will  be  reduced  by  3.5  per  cent, 
making  an  actual  efficiency  of  251.  This  divided  into  the  total  heat  require- 
ments gives  91  sq.  ft.  of  heating  surface  required,  which  is  supplied  by  two 
units  of  46%  sq.  ft.  each  as  marked  on  the  plan. 

Data  as  above  for  determination  of  the  other  units  are  marked  on  the 
plan.  Room  7,  which  is  to  be  heated  by  indirect  surface,  is  calculated 
as  follows:  The  total  requirements  for  the  east  side  are  13058  B.t.u.  per  hr., 
and  assuming  that  the  air  enters  the  room  at  120  deg.  fahr.,  the  pounds  of 
air  required  in  accordance  with  formula  on  Page  54  would  be  18.2  per  minute. 

Vento  radiation  30  inches  long  on  4-in.  centers  gives  a  temperature 
rise  of  air  from  zero  to  120  deg.  fahr.  at  100  ft.  per  min.  velocity,  measured 
at  70  deg.  fahr.  volume.  The  free  area  per  section  is  0.225  sq.  ft. 

The  pounds  of  air  as  found  above  divided  by  the  density  at  70  deg. 
fahr.,  or  0.0749,  gives  244  cu.  ft.  of  air  per  minute. 

This  volume  divided  by  the  velocity,  then  by  the  free  area  per  section, 
gives  eleven  sections  required. 

The  distance  from  the  center  of  the  radiation  to  the  floor  above  is  27 
inches,  which  head  with  120  deg.  fahr.  temperature  difference  gives  a  theo- 
retical velocity  of  367  ft.  per  min.,  by  the  formulae  on  Page  54.  For 
determining  the  size  of  the  ducts,  one-half  of  this  value,  or  184  ft.  per  min. 
velocity  may  be  used. 

Using  formula  on  Page  54  with  a  density  for  air  at  120  deg.  fahr.,  the 
area  of  the  hot-air  duct  is  208  sq.  in.  The  register  if  of  66%  per  cent 
free  area  should  contain  312  sq.  in. 

The  cold-air  duct  by  the  above  formula,  using  air  density  at  zero, 
should  have  a  sectional  area  of  165  sq.  in. 

The  indirect  surface  for  the  requirement  of  the  west  side  of  this  room 
was  calculated  similarly. 

As  another  example,  to  determine  the  radiation  necessary  to  supply  the 
heat  required  for  the  factory  building  as  calculated  in  the  previous  chapter 
and  shown  in  Figure  5-2,  Page  37. 

Assume  that  steam  at  10-lb.  per  sq.  in.  pressure  or  at  a  temperature  of 
240  deg.  fahr.  is  available  for  heating  this  building  under  maximum  load 
conditions.  The  increase  in  B.t.u.  emission  of  the  heating  surfaces  for  this 
increased  temperature  above  the  standard  or  basic  temperature  is  20  per 
cent,  and  there  would  be  a  further  increase  in  efficiency  of  3  per  cent  due 
to  a  65-deg.  fahr.  instead  of  70-deg.  fahr.  room  temperature. 

This  would  make  a  total  increase  of  23.6  per  cent  in  B.t.u.  emitted  per 
hour  per  sq.  ft.  of  heating  surface  for  this  installation,  over  the  basic  value. 

The  monitor  portion  of  the  building  is  provided  with  IJ^-in.  pipe 
coils  under  the  windows,  with  expansion  springs  at  the  ends,  as  shown.  For 
the  lower  portion  of  the  building  cast-iron  wall  surface  is  to  be  installed 
as  shown.  The  efficiency  of  the  heating  surface  and  method  of  determining 
the  amount  of  surface  are  shown  on  the  plan. 

88 


CHAPTER  VII 

Ventilation  Problems  as  They  Affect  the  Design 

of  Heating  Systems 

"T  TENTILATION  in  the  past  was  based  on  more  or  less  traditional 
y  and  unscientific  standards,  but  is  now  receiving  more  of  the  con- 
sideration warranted  by  its  importance. 

The  necessity  of  providing  adequate  ventilating  facilities  for  public 
buildings  and  buildings  for  various  classes  of  industrial  operations  has  been 
recognized  by  the  legislative  bodies  of  numerous  states  and  cities,  which 
have  passed  laws  and  ordinances  governing  the  quantity  of  air  to  be  supplied 
per  person,  and  in  some  instances  also  the  locations  from  which  the  air  supply 
is  to  be  brought  into  the  room  and  the  vitiated  air  removed. 

Ventilation  is  classed,  and  rightly  so,  as  a  branch  of  applied  science, 
and  it  is  the  duty  of  the  ventilating  engineer  to  apply  the  principles  of  this 
science  to  the  problems  with  which  he  is  dealing  in  such  a  manner  that  the 
results  obtained  will  produce  the  most  healthful  and  comfortable  conditions 
in  the  ventilated  rooms. 

A  ventilating  system  may  be  very  satisfactory  in  regard  to  the  quantity 
and  means  of  distribution  of  the  air  but  still  fail  to  produce  healthful  and 
comfortable  conditions.  A  good  ventilating  system  should  produce  im- 
mediate physical  comfort.  The  human  body  is  the  best  indicator  as  to 
whether  or  not  these  conditions  are  realized. 

Temperature  and  relative  humidity  are  important  factors  in  producing 
comfort :  the  human  body  is  to  a  great  extent  influenced  by  the  temperature 
of  the  surrounding  air,  and  by  the  rate  at  which  perspiration  is  evaporated 
from  the  body  into  the  air,  which  again  is  influenced  by  the  relative  humidity 
of  the  air. 

It  is  generally  considered  that  the  dry-bulb  temperature  to  produce  a 
sense  of  comfort  to  a  person  at  rest  is  68  to  70  deg.  fahr.,  provided  a  proper 
relation  between  the  dry  and  wet-bulb  temperatures  is  maintained. 

The  human  organism  is  very  susceptible  to  abrupt  changes  such  as 
might  be  experienced  when  passing  from  outdoors  on  a  cold  day  into  a 
heated  room  in  which  the  relative  humidity  is  below  normal  or  vice  versa. 

A  ventilating  system,  to  produce  conditions  of  comfort  and  health, 
should  therefore  provide  for  maintaining  a  satisfactory  relation  between 
temperature  and  humidity.  This  relation,  with  a  room  temperature  of 
68  to  70  deg.  fahr.,  generally  assumes  a  relative  humidity  not  below  40  per 
cent,  nor  over  60  per  cent.  Although  this  assumption  is  entirely  traditional, 
a  relation  of  humidity  to  temperature  may  be  found  between  the  limits  of 
which  true  comfort  will  result. 

Investigations  from  time  to  time  by  various  engineering  organizations 
and  civic  bodies  regarding  ventilating  methods  employed  in  public  buildings, 
and  particularly  in  schools,  have  disclosed  the  fact  that  systems  of  complete 
hot-blast  heating  and  ventilation  have  inherent  defects.  Many  former 

59 


advocates  of  this  type  of  equipment  now  favor  the  more  modern  types  of 
"split  system." 

It  has  been  proved  improper  from  the  standpoint  of  health  and  com- 
fort to  employ  a  small  quantity  of  highly  heated  air  to  replace  the  heat  lost 
by  transmission.  The  air  supply  should  be  large  in  volume  and  compara- 
tively low  in  temperature  in  order  to  obtain  the  best  ventilating  effect.  The 
nearer  the  temperature  of  the  incoming  air  corresponds  to  the  room  temper- 
ature to  be  maintained,  the  more  nearly  is  the  ideal  condition  obtained. 

To  compensate  for  the  heat  losses  through  wall  and  glass  and  other 
exposures,  direct  radiating  surface  should  be  installed.  This  direct  radiat- 
ing surface,  if  placed  under  the  windows,  will  also  overcome  the  difficulties 
due  to  "outside  wall  and  window  chill"  which,  in  the  hot-blast  system  of 
heating,  has  been  a  source  of  considerable  discomfort. 

The  close  relation  of  ventilation  and  heating  makes  necessary  a  discus- 
sion as  to  the  effect  of  various  methods  of  ventilation  upon  the  design  of  the 
heating  plant.  To  illustrate  these  effects,  some  of  the  commonest  applica- 
tions of  ventilation  may  be  classified  as  follows: 

The  fireplace. 

Direct-indirect  system  of  heating  and  ventilation. 

Indirect  system  of  gravity  ventilation. 

Ventilating  systems  for  school  buildings. 

Ventilating  systems  of  large  theatres  and  auditoriums. 

Ventilation  of  churches. 

Ventilation  of  banquet  halls,  dining  rooms,  kitchens,  etc. 

Exhaust  ventilation  of  industrial  plants. 

Hot-blast  systems  of  heating  for  industrial  plants. 

THE  FIREPLACE  :  The  purpose  of  fireplaces  is  twofold,  first,  ornamental 
effect,  and  second,  utility  for  warming  at  times  when  the  heating  plant  is 
not  in  operation.  Incidentally,  also,  the  flue  or  chimney  of  the  fireplace 
acts  as  a  vent,  the  chimney  effect  or  flue  draft  causing  continuous  outflow 
of  air  from  the  room  into  the  atmosphere. 

This  outflow  of  air  from  the  room  through  the  chimney  of  the  fireplace 
has  the  tendency  of  lowering  the  air  temperature  and  pressure  in  the  room, 
causing  a  greater  infiltration  of  air  from  outdoors  than  would  take  place 
without  the  fireplace.  The  additional  air  finding  its  way  into  the  room 
tends  to  lower  the  temperature,  unless  compensation  is  provided  in  the  form 
of  sufficient  additional  radiating  surface. 

DIRECT-INDIRECT  SYSTEM  OF  HEATING  AND  VENTILATION  :  This  method 
of  heating  and  ventilation,  as  described  in  Chapter  6,  has  come  into  quite 
general  use  in  certain  sections  of  the  country  for  ventilating  school  buildings, 
public  libraries  and  courthouses. 

INDIRECT  SYSTEM  OF  GRAVITY  VENTILATION:  Heating  by  the  indirect 
system,  in  which  the  heat  is  conveyed  entirely  by  air  to  the  space  to  be 
heated,  also  provides  a  fair  means  of  ventilation,  but  is  open  to  the  objection 
of  highly  heated  incoming  air. 

The  amount  of  air  to  be  circulated  is  generally  stipulated,  which  re- 
quires knowing  the  temperature  to  which  the  incoming  air  is  to  be  heated 

60 


so  that  in  cooling  from  incoming  to  maintained  room  temperature,  enough 
heat  units  will  be  provided  to  offset  the  heat  losses  through  windows,  w  alls, 
and  other  exposures. 

In  designing  heating  plants  of  the  indirect  type,  the  total  air  to  be 
circulated  must  be  known  within  a  fair  degree  of  accuracy  in  order  to  deter- 
mine the  quantity  of  steam  required. 

The  indirect  method  of  heating  requires  from  three  to  four  times  the 
quantity  of  steam  that  would  be  needed  with  direct  radiation  for  the  same 
warming  effect.  This  indicates  the  importance  of  carefully  considering 
ventilating  problems  in  connection  with  heating  systems,  in  order  to  determine 
proper  proportions  for  boilers,  pipes,  radiator  supply  valves,  return  traps, 
and  any  other  heating  system  apparatus  which  would  be  affected  by  the  in- 
creased steam  requirement  due  to  the  ventilating  equipment. 

With  the  indirect  system  it  is  also  necessary  to  provide  aspirating 
radiators  in  the  vent  flues. 

The  method  of  computing  indirect  radiating  surface  for  given  heating 
effects  and  requirements  is  discussed  in  Chapter  6. 

VENTILATING  SYSTEMS  FOR  SCHOOL  BUILDINGS:  The  direct-indirect 
and  the  indirect  systems  of  heating  previously  mentioned  are  frequently 
used  for  ventilating  school  houses  of  the  smaller  type,  but  for  buildings  of 
larger  proportions  mechanical  systems  of  ventilation  are  generally  installed. 

The  necessity  for  healthful  and  comfortable  conditions  in  school  build- 
ings has  been  the  main  stimulus  for  enacting  ventilating  laws  by  various 
states  and  cities. 

Great  progress  has  been  made  in  late  years  in  the  design  of  ventilating 
plants  for  school  buildings.  The  antiquated  hot-blast  system  of  heating 
and  ventilation  without  provision  for  humidification  has  been  almost 
entirely  abandoned  and  superseded  by  the  modern  split-system  method  of 
ventilating  with  tempered  air,  washed  and  humidified  before  being  delivered 
into  the  rooms.  Direct  radiation  is  installed  for  taking  care  of  the  heat  lost 
through  direct  exposures  of  walls,  windows,  doors,  etc. 

Air  is  generally  supplied  to  the  class  rooms  through  registers  or  dif- 
fusers  placed  at  a  level  of  seven  to  eight  feet  above  the  floor  with  the  vent 
registers  near  the  floor.  The  most  satisfactory  arrangement  is  generally 
obtained  where  the  heat  and  vent  flues  are  placed  in  the  corridor  walls  and 
the  air  is  blown  towards  the  windows.  The  vitiated  air  is  discharged  from 
the  vent  flues  into  ventilators  in  the  roof  to  the  atmosphere. 

The  cold  air  intake  should  preferably  be  at  a  point  above  the  roof. 
The  intake  openings  are  dampered,  and  additional  air  intake  openings  are 
provided  in  the  attic  space,  making  the  re-circulation  of  air  from  the  building 
possible  during  the  heating-up  period  in  the  morning.  Delivering  the  air 
into  the  rooms  at  nearly  the  temperature  to  be  maintained  and  with  auto- 
matic temperature  control  or  modulation  supply  valves  on  the  direct  radia- 
tors, gives  ideal  conditions  as  near  as  obtainable. 

In  computing  the  requirements  for  direct  heating  in  the  ventilated  spaces, 
it  is  only  necessary  to  take  into  account  the  heat  losses  due  to  exposures. 
Exceptions,  however,  must  be  made  of  rooms  which  are  to  be  in  use  after  the 
ventilating  system  is  shut  down,  such  as  libraries,  reading  rooms  and  offices. 

61 


Fig.  7-1.     Arrangement  of  fresh  air  inlet  with  diffusers,  vent  outlet  and  direct  radiators 

in  a  modern  school  room 

Ventilating  systems  of  school  buildings  are  usually  shut  down  after 
the  close  of  the  afternoon  session.  Any  rooms  that  may  be  in  use  after 
that  period  should  have  sufficient  direct  radiation  to  take  care  of  the  maxi- 
mum requirements  without  the  assistance  of  the  ventilating  system. 

The  steam  required  to  temper  the  air  needed  for  the  ventilating  system 
is  generally  greatly  in  excess  of  that  required  for  the  direct  system  of 
heating. 

Where  air  washers  and  humidity -control  systems  are  installed,  addi- 
tional steam  is  required  to  add  to  the  heat  in  the  air,  compensating  for  the 
drop  in  temperature  in  passing  through  the  air  washer  and  to  supply  the 
humidity  control  apparatus. 

Masonry  ducts  under  floors,  if  used  for  the  main  trunk  supply  system 
for  air  distribution,  should  be  so  constructed  that  they  can  be  kept  dry  at 
all  times.  This  can  be  accomplished  by  the  use  of  a  reliable  system  of 
waterproofing.  The  cooling  effect  of  these  masonry  ducts  must  be  considered 
in  the  design  of  heating  and  ventilating  plants  and  during  the  heating-up 
period  sufficient  time  should  be  allowed  for  heating  the  ducts  thoroughly. 

The  entire  heating  plant,  including  boilers,  vacuum  pumps,  piping 
system  and  direct  radiation,  is  affected  by  the  method  of  ventilation.  In 
the  design  of  the  plant  all  phases  of  the  application  and  operation  of  the 
ventilating  system  must  therefore  be  known  and  analyzed  to  make  possible 
a  well  balanced  system. 

62 


VENTILATION  OF  THEATRES  AND  AUDITORIUMS:  The  ventilation  of 
theatres  and  auditoriums  presents  an  entirely  different  problem  from  that 
encountered  in  the  ventilation  of  a  building  subdivided  into  a  number  of 
comparatively  small  rooms. 

The  problem  of  proper  air  distribution  in  large  spaces  with  seating 
capacities  numbering  into  thousands  requires  special  study  to  provide 
the  required  quota  of  fresh  air  for  each  occupant. 

\  cntilating  systems  for  theatres  and  auditoriums  are  usually  operated 
only  during  the  performances,  so  that  portions  of  the  structure  which  are  in 
use  at  oilier  limes  should  be  heated  by  direct  radiation. 

The  quantity  of  air  supplied  to  theatre  auditoriums,  on  the  basis  of 
30  cu.  ft.  per  mm.  per  occupant,  is  usually  so  large  that  sufficient  heat 
is  supplied  by  delivering  the  air  into  the  space  at  a  temperature  a  few 
degrees  higher  than  that  to  be  maintained.  The  temperature  regulating 
system  should  be  flexibile  enough  to  automatically  reduce  the  incoming 
air  temperature  when  a  large  percentage  of  the  seats  are  occupied,  and  in  this 
way  prevent  excessive  temperature  rise  in  the  room. 

The  modern  theatre  would  not  be  complete  without  the  installation  of 
air  washers,  humidity -control  system,  and,  for  summer  use,  a  refrigerating 
system  for  cooling  the  air. 

The  design  of  heating  and  ventilating  systems  for  large  auditoriums 
presents  an  interesting  problem  in  engineering.  One  is  so  closely  affected 
by  the  other  that  both  should  be  worked  out  together  so  that  the  results 
obtained  will  harmonize. 

VENTILATION  OF  CHURCHES:  Ventilation  for  churches  is  usually 
applied  only  to  the  main  auditorium  and  Sunday-school  room,  the  balance 
of  the  building  being  heated  by  direct  radiation.  Most  churches  are  not 
continuously  heated,  and  the  warming-up  period  should  on  that  account 
receive  careful  consideration  by  the  designer.  The  ventilating  system  is 
generally  operated  during  the  Sunday  services  only. 

Whether  to  use  the  up-flow  system  of  air  distribution  or  to  discharge 
the  air  into  the  room  through  registers  in  the  wall  will  greatly  depend  on  the 
size  of  the  room  to  be  ventilated.  In  large  churches,  a  combination  of  both, 
blowing  in  the  air  partly  through  openings  in  the  floors  in  the  aisles,  and  partly 
through  registers  in  the  walls,  will  give  good  results.  Vent  openings  are 
usually  placed  in  the  walls  near  the  floor  and  in  the  ceiling. 

The  ventilating  system  for  a  church  should  supply  air  for  ventilation  only 
and  no  attempt  should  be  made  to  use  the  fan  system  for  heating.  For 
satisfactory  results,  sufficient  direct  radiation  should  be  provided  to  com- 
pensate for  all  heat  losses  due  to  direct  exposures  and  infiltration.  Arrange- 
ment for  re-circulating  the  air  before  the  building  is  occupied  will  be  found  a 
convenience,  both  from  the  standpoint  of  shortening  the  warming-up  period 
and  also  of  effecting  a  considerable  economy  in  the  fuel  consumption. 

It  is  considered  good  practice  to  have  a  separate  boiler  and  piping 
system  for  that  part  of  the  heating  and  ventilating  plant  which  will  be  in  use 
Sundays  only,  having  another  boiler  to  heat  the  portions  of  the  church  in 
use  during  week  days. 

63 


VENTILATION  OF  BANQUET  HALLS,  DINING  ROOMS,  MEETING  ROOMS, 
ETC.  :  In  no  other  class  of  ventilated  rooms  is  the  efficiency  or  inefficiency 
of  the  ventilating  system  so  noticeable  as  in  banquet  halls,  dining  rooms  and 
meeting  rooms.  Smoke-laden  air  indicates  that  the  ventilating  system  is 
not  functioning  properly,  while  if  the  air  is  clear  and  fresh  in  spite  of  smoking 
by  the  guests,  a  satisfactory  diffusion  of  air  in  the  room  is  shown. 

As  already  pointed  out  in  connection  with  other  ventilating  problems, 
the  air  should  be  brought  in  as  nearly  at  room  temperature  as  possible,  and 
if  heating  of  the  room  involves  consideration  of  outside  exposures,  direct 
radiation  should  be  used.  The  location  and  distribution  of  the  exhaust  open- 
ings is  of  prime  importance  and  the  exhaust  should  be  accomplished  by 
mechanical  means.  Vent  openings  should  be  placed  near  both  floor  and 
ceiling,  and,  if  the  structural  conditions  permit,  additional  vents  should  be 
provided  in  the  ceiling  toward  the  center  of  the  room. 

Kitchens  require  a  very  large  air  change,  which  should  be  accomplished 
by  means  of  exhaust  fans.  Ordinances  of  some  cities  specify  a  three-minute 
air  change  for  hotel  kitchens,  requiring  a  separate  steel  vent  stack  to  be 
extended  through  the  roof  for  this  purpose.  An  exhaust  fan,  with  inlet 
connected  to  this  vent  shaft,  is  usually  placed  in  the  penthouse.  Above  the 
point  where  the  fan  inlet  connection  is  made,  a  tight-fitting  damper  propped 


Angle  Iron  Frame  bolted 
to  Duct  and  anchored  to 
Brickwork 


:eel  Plate  Fire  Damper 


..j.  12  U.S.G.  Door 
with  Angle  Iron  Frame 


-  No 


Fig.  7-2.     Arrangement  of  fan,  vent  stack  and  safety  damper  of  ventilating  equipment  for  a  kitchen 

64 


open  with  bar  iron  having  a  fusible  link  is  placed  in  the  vent  shaft,  and  the 
fan  discharge  is  reconnected  to  the  vent  shaft  above  this  damper.  In  case 
the  fusible  link  is  melted,  the  damper  in  the  fan  intake  drops  by  gravity, 
closing  the  fan  inlet  and  the  stack  is  opened  to  the  atmosphere.  This 
permits  the  stack  to  burn  out  without  damaging  the  exhaust  fan. 

W7here  kitchens  adjoin  the  dining  rooms,  the  latter  can  conveniently 
be  exhausted  through  the  kitchen.  This  greatly  reduces  the  inflow  of  air 
from  outdoors  into  the  kitchen  and  at  the  same  time  prevents  odors  from 
the  kitchen  from  flowing  into  the  dining  room. 

Where  existing  conditions  do  not  permit  induction  of  air  from  warmed 
spaces  to  replace  that  exhausted,  the  air  must  necessarily  find  its  way  into 
the  kitchen  from  outdoors  and  provision  must  be  made  to  prevent  a  drop 
below  the  desired  temperature.  This  is  best  accomplished  by  installing 
direct  or  indirect  radiation  for  heating  to  the  temperature  needed. 

Considerable  heat  is  produced  by  the  ranges  and  steam  cooking  utensils, 
so  that  the  kitchen  may  be  overloaded  with  radiation  unless  complete  in- 
formation is  available  as  to  the  kitchen  equipment  to  be  used. 

EXHAUST  VENTILATION  OF  INDUSTRIAL  PLANTS:  Industries,  which  in 
their  operations  produce  dust,  acid  fumes,  or  in  any  other  way  contaminate 
(lie  air,  require  positive  means  for  removing  the  dust  or  fume-laden  air  from 
_  the  premises.  Mechanical  systems  of  exhaust  ventilation  are 
used  to  maintain  a  continuous  air  change  by  exhausting  the 
dust-laden  air. 

Various  types  of  machines,  such  as  grinders,  buffers  and 
wood-working  machines,  are  provided  with  sheet-metal  ducts 

running  to  the  exhaust  fans, 
which  are  usually  centrally  locat- 
ed, and  discharge  either  into 
dust-collecting  chambers  or  into 
the  atmosphere,  depending  upon 
the  nature  of  the  dust  or  refuse 
to  be  handled. 

The  continuous  exhausting 
of  air  from  any  space  will  cause 
a  corresponding  inflow  of  out- 
door air  which  must  be  heated 
to  avoid  lowering  the  inside 
temperature. 

If  the  ventilated  spaces  have  out- 
side exposures,  the  air  is  drawn  directly 
from  outdoors,  and  infiltration  takes 
place  uniformly  over  the  entire  exposed 
area.  A  sufficient  amount  of  direct  heat- 
ing surface  to  heat  this  air  to  the  temper- 
ature to  be  maintained  must  be  added  to 
the  heating  surface  required  for  heating 
I  he  space  without  the  exhaust  system. 

65 


rOOOQCO 

mmmmMWt 


7-3.    Indirect  radiation  <-<m- 
in'i -li'd  for  ;iir  supply  through  a  wall. 


The  vise  of  large  indirect  radiation  connected  for  air  supply  through 
window  or  other  opening  in  outside  wall,  as  shown  in  Fig.  7-3,  has  been  found 
in  practice  to  be  an  excellent  method  for  warming  the  infiltrated  air  necessary 
to  replace  that  removed  by  an  exhaust  fan  system.  In  connection  with 
temperature  control  of  the  warmed  air  this  method  has  proved  highly 
efficient. 

If,  however,  the  ventilated  space  has  no  direct  exposure  and  connects 
with  other  rooms  so  that  the  air  will  be  drawn  from  these,  the  additional 
radiation  must  be  placed  in  the  rooms  from  which  the  air  is  drawn  or  indirect 
inlets  must  be  provided. 

Chemical  plants  requiring  the  removal  of  acid  fumes  must  usually 
exhaust  large  volumes  of  air  from  the  rooms,  and  an  equivalent  quantity 
of  air  must  be  admitted  directly  from  outdoors.  This  air  is  generally  ad- 
mitted through  special  openings  in  the  walls  and  is  drawn  through  tempering 
coils,  so  that  it  enters  the  room  at  the  temperature  to  be  maintained.  In 
such  cases  the  heating-up  requirement  can  be  eliminated  from  the  heat  loss 
calculations,  and  the  direct  radiation  should  be  sufficient  only  to  compensate 
for  the  losses  through  direct  exposures  and  infiltration.  However,  where 
the  exhaust  system  is  in  use  only  at  intervals,  allowances  for  heating  up 
the  contents  of  the  room  should  be  made  in  figuring  the  warming-up  period. 
Sufficient  direct  radiation  should  be  added  to  supply  the  heat  units  required 
for  this  purpose. 

HOT-BLAST  SYSTEMS  OF  HEATING  FOR  INDUSTRIAL  PLANTS:  In  indus- 
trial structures,  such  as  large  foundries,  machine  shops,  erecting  shops  and 
round-houses,  the  hot-blast  system  of  heating,  instead  of  the  direct  method, 
is  often  selected,  owing  to  its  lower  first  cost.  From  the  operating  stand- 
point, however,  the  hot-blast  system  is  considerably  more  expensive  than 
the  direct,  because  of  the  greater  amount  of  steam  required  for  heating  by 


Fig.  7-4.     Arrangement  of  hot-air  ducts  of  hot-blast  system  in  an  industrial  plant.     The  side  walls  are 
protected  by  direct  radiation  placed  under  windows 


66 


any  indirect  method.  This  condition  is  particularly  apparent  in  cases  where 
all  the  air  is  taken  directly  from  outdoors  and  after  being  circulated  through 
the  space  is  discharged  into  the  atmosphere. 

Where  air  can  be  taken  from  the  space  to  be  heated  and  re-circulated, 
instead  of  taking  it  from  outdoors,  the  steam  requirements  are  considerably 
reduced.  In  either  case,  the  air  must  be  heated  at  the  fan  to  such  a  tem- 
perature that  in  cooling  from  the  air-outlet  temperature  to  that  maintained 
inside,  all  heat  losses  are  offset  under  maximum  conditions. 

Only  a  few  general  ventilating  problems  and  their  direct  effect  upon 
heating  plant  design  have  been  mentioned  in  this  chapter,  but  these  show 
the  importance  of  analyzing  each  problem  thoroughly  and  making  all 
necessary  provisions  for  the  ventilating  system  in  heating  system  design. 

Factors  Entering  Design  of  Complete  Heating  and 
Ventilating  Plant 

AIR  QUANTITIES  REQUIRED  FOR  VENTILATION:  Air  quantities  in  many 
states  and  municipalities  are  fixed  by  legal  restrictions  which  must  be  followed. 
However,  some  of  the  generally  accepted  standards  are  mentioned  here. 

The  type  of  building  and  the  purpose  for  which  it  is  to  be  used  are  the 
main  factors  entering  into  the  design  of  any  ventilating  system,  not  only 
as  to  the  type  of  ventilation  which  is  best  adapted  to  each  particular  problem, 
but  also  as  to  the  volume  of  air  required. 

Tables  7-1,  7-2,  and  7-3  list  kinds  of  buildings,  together  with  their  air 
requirements  and  allowable  air  velocities.  These  quantities,  with  slight 
variation,  have  been  universally  adopted. 

Table  7-1.     Air  Requirements  of  Various  Buildings 

Type  of  building  Air  supply.    Cu.  ft.  per  occupant  per  hr. 

School  buildings 1800 

Theatre  and  assembly  halls 1500 

Churches 1500 

Prisons 2100 

{Ordinary 2600 
Wounded 3500 
Contagion 6000 

Residence 1600  to  2000 

Factories 2000  to  3000 


Table  7-2.    Allowable  Air  Velocities.    Public  Building  Work.    Fan  Systems 


Supply  air 

Exhaust  air 

Cold-air  intake                      700-1000  ft.  p 
Cloth  filters                             About  40  " 
Air  washers                                          500  " 
Indirect  heaters  (Vento)        800-1200  " 
Horizontal  air  ducts             1000-1200  " 
at  fan,  decrees 
ft.  at  base  of  f 
Vertical  flues  (masonry)                   300  ft.  p 
Vertical  (lues  (sheet-metal)             600  " 
Register  outlets                        200-300  " 

IT  inin. 

ng  to  600 
ues. 
or  min. 

Register  outlets                        300-400  ft.  per  min. 
Vertical  flues  (masonry)                  400  " 
\  crlical  flues  (sheet-metal)            500  " 
Horizontal  ducts                              600  " 
at  far  end  up  to  1000  at 
fan  inlet. 
Fan  discharge  outlet            700-1000  ft.  per  min. 

For  air  outlets  15  ft.  or  more  above  floor  velocity 
may  be  as  high  as  350  ft.  per  min.  if  not  thrown 
directly  down  on  prrsons  below. 


67 


Table  7-3.    Allowable  Air  Velocities  in  Various  Buildings  in  Feet  per  Minute 


Horizontal 
ducts 


Vertical 
risers 


Outlets 


1500  to  2800 

900  to  1500 

600  to  1200 

1000  to  1800 

500  to  750 

300  to  500 

1000  to  1800 

500  to  750 

300  to  600 

Theatres  

1000  to  1800 

500  to  750 

300  to  600 

1000  to  1800 

500  to  750 

300  to  600 

SIZING  OF  THE  DUCTS:    Two  methods  of  estimating  are  in  common  use: 

First,  the  velocity  method,  in  which  the  velocity  is  fixed  in  the  various 
portions  of  the  system,  and  decreases  from  the  fan  outlet  to  the  various 
points  of  discharge.  This  method  is  applicable  in  single-duct  systems  and 
in  public  buildings  layouts,  where  the  law  requires  certain  velocity  standards. 

Referring  to  the  duct  design  in  Fig.  7-5,  certain  volumes  and  velocities 
are  given.  To  determine  the  size  of  ducts  at  any  particular  point,  the  vol- 
ume in  cubic  feet  of  air  passing  that  point  is  divided  by  the  velocity  in  feet 
at  that  point,  which  gives  the  required  area  in  square  feet. 

Determination  of  the  friction  in  any  part  of  the  duct  is  made  by 
reference  to  the  friction  chart,  Figure  7-7. 

In  a  single-duct  system,  the  longest 
duct,  or  the  duct  requiring  greatest  pres- 
sure, should  be  designed  for  certain  veloci- 
ties and  the  total  pressure  required  at  the 


,5}  Sq.  Ft.  Free  Area 


y  Sq.  Ft.  Free  Aiea 


1200  Cu.  Ft. 


1200  Cu.  Ft. 


~2fSq.  Ft.  Free  Area 


/ 

i  —    /                  y  /    / 

'            M 

V          \ 

__J 

1200'Vel. 


Fig.  7-5.  Arrangement  of 
ducts  in  a  trunk-line  system. 
Sized  by  the  velocity  method 


1000'Vel. 


900  Vel- 


-900  Vel. 


-I-jSq.  Ft.  Free  Area 


1200  Cu.  Ft. 


1500  Cu.  H. 


1200  Cu.  Ft. 


plenum  chamber  determined  from  the  friction  chart,  Figure  7-7.  All  other 
ducts  should  then  be  designed  for  the  same  pressure. 

Second — The  friction-loss  method,  in  which  the  duct  is  proportioned 
for  equal  friction  pressure  loss  in  every  foot  of  run. 

This  method  of  duct  sizing  necessitates  assumption  of  the  velocity 
and  volume  at  the  outlets,  and  is  adaptable  to  trunk-line  duct  systems  such 
as  are  common  in  factories. 

Table  7-4  gives  an  easy  and  accurate  method  for  sizing  ducts  by  pres- 
sure loss  method.  An  example  of  its  application  follows  (See  Figure  7-7) : 

Assuming  a  1000  cu.  ft.  discharge  from  each  outlet  at  1000  ft.  velocity 
per  min.  the  area  of  the  outlet  is  1  sq.  ft.  or  say  14  in.  in  diameter. 

Referring  to  Table  7-4,  a  14-in.  pipe  is  equivalent  to  737  1-in.  pipes 


68 


1000  Cu.  Ft. 


1000  Cu.  Ft. 


1000  Cu.  Ft. 
14 


29  — 


1000  Cu. 


.Ft.  lOOOCu.Ft.  lOOOCu.Ft. 


"S" 


29- 


Fig.  7-6.  AmngBBMBl  of  ilucts  in 
a  trunk-line  system.  Sized  by  the 
pressure-drop  method 


Velocity  at  Outlets,  1000  Ft.  per  Min. 


1000  Cu.  Ft.  1000  Cu.  Ft.  1000  Cu.  Ft. 

"I 


1000  Cu.  Ft. 


1000  Cu.  Ft. 


and  two  14-in.  pipes  are  equivalent  to  1474  1-in.  pipes.  Also,  1474  1-in. 
pipes  are  equivalent  to  approximately  a  19-in.  pipe,  and  so  on.  To  deter- 
mine velocity  at  any  point,  the  volume  there  is  divided  by  the  area  in  sq.  ft. 
To  determine  friction  in  any  portion  of  duct  refer  to  Fig.  7-7. 

CALCULATION  OF  RESISTANCE  OR  PRESSURE:  It  is  not  the  intention 
to  go  into  the  many  complex  formulae  entering  into  the  loss  of  pressure 
in  ducts  but  rather  to  arrange  some  easily  workable  method. 

Table  7-4.     Comparison  of  the  Air-carrying  Capacity  of  Various  Sizes  of  Pipes 
with  That  of  a  1-in.  Pipe  of  Same  Length  and  Equal  Friction  Pressure  Loss 

Example • — With  an  equal  pressure  loss  and  equal  length,  a  4-in.  diameter  pipe  will  curry  the  same 
volume  of  air  as  thirty-two  1-in.  pipes. 


Diam. 

1"  Pipes 

Diam. 

1"  Pipes 

Diam. 

1"  Pipes 

Diam. 

1"  Pi  pes 

Diam. 

l"Pipe. 

1 

1 

21 

1985 

41 

10565 

61 

28850 

81 

59122 

2 

5 

22 

22:>0 

li- 

11300 

62 

30200 

82 

60831 

3 

16 

23 

2r>2:> 

43 

12030 

63 

31350 

83 

625  10 

4 

32 

21 

2800 

44 

12621 

64 

32500 

81 

61210 

5 

56 

2.-. 

3060 

15 

13100 

65 

3397:> 

85 

(.(>:!96 

6 

88 

26 

:!  I2:> 

46 

1  1100 

66 

35300 

86 

68512 

7 

129 

27 

3738 

47 

15000 

67 

36600 

!!7 

-0687 

8 

180 

28 

4100 

48 

15850 

68 

38000 

88 

-2»:« 

9 

211 

2<> 

II  10 

49 

16610 

69 

39275 

89 

74979 

10 

:tl7 

30 

1898 

50 

17600 

70 

40250 

90 

'7125 

11 

102 

31 

5312 

51 

18275 

71 

41995 

91 

-<)271 

12 

501 

32 

:>6:il 

52 

19335 

72 

43710 

92 

81116 

13 

613 

33 

6151 

53 

20000 

73 

45449 

93 

83562 

1  1 

7:!7 

34 

6675 

54 

21500 

74 

17158 

91 

85708 

15 

876 

35 

7075 

55 

22300 

75 

48887 

95 

8785  1 

16 

1026 

36 

77I55 

56 

2:!  150 

76 

50576 

96 

89999 

17 

II  <)7 

:i7 

8265 

:.7 

2  1500 

77 

52285 

18 

137:. 

38 

«7I5 

58 

25600 

78 

539<)r, 

19 

1580 

39 

9350 

59 

26700 

79 

:,:>70l 

20 

177:, 

to 

10060 

60 

27700 

80 

57413 

The  friction  chart,  Figure  7-7,  (based  on  accepted  pressure  loss  formu- 
lae) provides  quick,  accurate  determination  of  pressure  loss. 

Example:  Assume  that  30000  cu.  ft.  of  air  per  minute  is  passed  through 
a  duct  40  in.  in  diameter  and  50  ft.  long.  From  the  30000  cu.  ft.  division 
at  the  right  of  chart,  trace  horizontally  to  intersection  with  the  line  repre- 
senting 40  in.  diameter  pipe.  Perpendicularly  down  from  this  point  the 


1.000,000 
800,000 

600.000 
500,000 

400,000 
300,000 

200,000 
150,000 

100,000 
80,000 

00,000 
50,000 

40,000 
30,000 

20,000   | 
15.000  'I 

I 
10,000   - 

8,000   <*• 

C,000    3 
5,000  ° 

4,000 
3,000 

2,000 
1,500 

1,000 
800 

GOO 
500 
400 

300 

200 

150 

100 


Friction  in  Inches  Water  Gauge  per  100  Feet 
Fig.  7-7.     Chart  for  determining  pressure  loss  in  ducts 
70 


Table  7-5.     Resistance  of  90-deg.  Elbows 


Radius  of  throat 
of  elbow  in 
diameters  of 
pipe 

Number  of  diameters 
of  straight  pipe 
offering  equivalent 
resistance 

Radius  of  throat 
of  elbow  in 
diameters  of 
pipe 

Number  of  diameters 
of  straight  pipe 
offering  equivalent 
resistance 

Vi. 

67.0 

2)4  

.  4.5 

H 

.  .      30  0 

g 

4.8 

•'  ,             

16.0 

314  

5.0 

10  0 

4             

5.2 

\y± 

7.5 

4%  

5.5 

\  i  . 

60 

5              

...     5.8 

i 

5  0 

.">  '  •> 

6.0 

.2               

43 

1'riction  in  inches  of  water  per  100  ft.  of  pipe  is  given — in  this  case  0.51  inches. 

For  50  ft.  the  friction  will  be  50  per  cent  of  0.5 1  or  0.27  in.  of  water. 
Friction  in  inches  of  water  multiplied  by  0.58  gives  friction  in  ounces. 

The  resistance  (Table  7-5)  is  expressed  as  that  of  the  number  of  diameters 
of  straight  pipe  of  same  diameter  as  the  elbow,  and  is  given  for  elbows  hav- 
ing different  radii  of  throat,  also  expressed  in  diameters  of  pipe.  For  instance, 
a  90-deg.  elbow  of  2-1-in.  pipe,  having  a  radius  of  throat  equal  to  1  diameter, 
that  is  24  inches,  offers  the  same  resistance  to  the  flow  of  air  as  10  diameters 
of  straight  pipe  or  20  ft.  of  straight  pipe. 


*i    - 

"I 

^ 

\ 

/ 

j 

jT 

» 

V 

—  •* 

/ 

/ 

/ 

:q 

IV 

g 

a 

)u 

I 

Ju 

VI' 

/ 

/ 

/ 

/ 

/ 

/ 

/ 

p 

/ 

/ 

/ 

, 

? 

/ 

/ 

/ 

/ 

A 

J 

E 

f 

s 

/ 

r"g^  +(B) 

s 

D 

f 

/ 

3.2S 

/ 

x 

^. 

X 

^> 

X* 

x 

^ 

1 

x 

X 

^ 

'x 

^, 

^ 

,x- 

7       U.S      0.0      1.0      1.1      1.2       1.3       1.4       1-5      1.6       1.7       1.8       1.9       2.0     -*       '-*•*      *-3      *•*       *-3      t«      2-7       *•*      *•»      3.0     3-1      W 

Kig.  7-8.    Curve  for  (li-tcriniiiinK  the  diaint-tcrs  of  round  pipes  having  tin-  smiie  friction  loss  for 
same  capacity  as  rectangular  ducts  of  various  dimensions 


To  the  resistance  of  the  duct  system  should  be  added  the  resistance 
through  tempering  and  reheating  coils,  also  air  washers,  plus  a  small  factor  of 
safety,  thereby  determining  the  total  pressure  against  which  the  fan  must 
deliver  the  specified  volume  of  air. 

Where  each  branch  duct  leaves  the  trunk  line,  there  should  be  a  volume 
damper  with  trunnion,  quadrant  and  locking  device,  for  balancing  the  system. 

Figure  7-8  is  a  curve  for  determining  diameter  of  round  pipe  having 
same  friction  for  same  capacity  as  rectangular  ducts  of  varying  dimensions. 

Selecting  the  Apparatus 

SIZES  AND  ARRANGEMENT  OF  FANS  :  For  fan  performances  and  capaci- 
ties, reference  should  be  made  to  tables  issued  by  the  manufacturers. 

Table  7-6.     Quantities  of  Air  at  Various  Temperatures  Which  Will  Be  Raised 

1  deg.  fahr.  by  1  B.t.u. 
Specific  heat  of  air  at  constant  pressure  is  0.2375.     At  zero  1  cu.  ft.  of  dry  air  weighs  0.0861  Ib.  and 


lib. 
.0864 


11.574  cu.  ft.  -^r  =  48.74  cu.  ft.  raised  1  deg.  by  1  B.t.u. 


Temp. 

Weight 

Cu.  ft.  l 

Temp. 

Weight 

Cu.  ft.  1 

Temp. 

Weight 

Cu.  ft.  1 

air  deg. 

of  1 

Cu.  ft. 

B.t.u.  will 

air  deg. 

of  1 

Cu.  ft. 

B.t.u.  will 

air  deg. 

of  1 

Cu.  ft. 

B.t.u.  will 

fahr. 

cu.  ft. 

in  1  Ib. 

raise  1 

fahr. 

cu.  ft. 

in  1  Ib. 

raise  1 

fahr. 

cu.  ft. 

in  1  Ib. 

raise    1 

deg.  fahr. 

deg.  fahr. 

deg.  fahr. 

0 

.  0864 

11.58 

48.74 

72 

.  0747 

13.39 

56.40 

152 

.  0649 

15.40 

64.90 

12 

.  0842 

11.87 

50.00 

82 

.  0733 

13.61 

57.40 

162 

.0638 

15.65 

66.00 

22 

.  082  1 

12.14 

51  .  00 

92 

.0720 

13.90 

58.60 

172 

.0628 

15.90 

67.00 

32 

.0807 

12.  10 

52.20 

102 

.0707 

14.14 

59.20 

182 

.0618 

16.17 

68.00 

42 

.0791 

12.64 

53.10 

112 

.  0694 

14.40 

60.60 

192 

.0609 

16.42 

69.10 

52 

.0776 

12.88 

51.10 

122 

.0682 

14.65 

61.60 

202 

.0600 

16.67 

70.10 

62 

.0761 

13.13 

55.20 

132 

.0671 

11.90 

62.80 

212 

.  0591 

16.92 

71.30 

70 

.  0750 

13.34 

56.30 

142 

.0660 

15.15 

63.80 

HEATERS  :  To  select  a  heater  for  any  set  of  conditions  it  is  necessary  to 
know  the  volume  of  air  to  be  handled,  its  initial  temperature,  and  the 
temperature  to  which  it  must  be  raised. 

Two  methods  for  determining  the  above  quantities  are  available 
where  the  building  is  heated  as  well  as  ventilated  by  the  air.  One  applies 
where  a  definite  air  change  is  desired  or  where  ventilation  must  be  provided 
for  a  given  number  of  people. 

Example:  Assume  a  building  requiring  18000  cu.  ft.  per  min.  measured 
at  70  deg.  fahr.  with  a  total  of  860000  B.  t.  u.  loss  through  exposed  glass,  walls, 
B.t.u.  loss  per  hr. 


etc.    Then 


Cu.  ft.  per  min.  X  .2375  X  .075  X  60 
860,000 


=  diffusion 


18000  X  .2375  X  .075  X  60 


=  45  deg.  fahr. 


45  deg.  diffusion  +  10  deg.  duct  loss  +  70  deg.  desired  room  temperature  = 
125  deg.  final  temperature  at  coils.  In  this  calculation  0.2375  is  the  specific 
heat  of  air  and  is  constant  and  0.075  is  the  weight  of  one  cubic  foot  of  air 
at  the  room  temperature  of  70  deg.  (See  Table  7-6.) 

The  other  method  is  to  decide  on  the  final  temperature  to  be  used  with 
some  fixed  entering  temperature. 

72 


Example:  Suppose  the  hourly  heat  loss  through  exposed  walls,  glass,  etc., 
is  1201500  B.t.u.  Assume  a  final  temperature  at  the  heater  of  135  deg. 
fahr.  and  a  loss  of  10  deg.  in  the  ducts.  The  temperature  at  the  duct 
outlets  will  then  he  125  deg.  fahr.  The  room  temperature  desired  is  65  deg. 
and  the  outside  temperature  is  0  deg. 

The  difference  in  the  temperature  between  the  duct  outlets  and  the 
room  temperature  is  available  for  heating. 

c     f  .  B.t.u.  per  hr.  =  1204500 

=  60  x  60  x  .2375  x  .068   "  60  X  60  x  .2375  x  .068 
20720  cu.  ft.  per  min.  required,  in  which  0.2375  is  specific  heat  of  air  and  is 
constant  and  0.068  is  weight  of  one  cu.  ft.  of  air  at  125  deg.  (See  Table  7-6.) 

Either  of  the  above  formula?  can  be  used  on  split  systems  where  a 
portion  of  the  losses  through  walls,glass,  etc.,  are  taken  care  of  by  direct  radia- 
tion, and  the  balance  by  the  incoming  air.  In  the  split  system  where  all 
heat  loss  through  walls,  glass,  etc.,  is  taken  care  of  by  direct  radiation,  the  final 
temperature  of  the  air  is,  of  course,  the  same  as  the  room  temperature  de- 
sired. However,  in  choosing  the  heater,  allowance  should  be  made  for  some 
temperature  drop  in  the  ducts  (usually  10  to  20  degrees). 

After  determining  the  volume  and  final  temperature  of  the  air  the  size 
of  heater  can  readily  be  chosen  from  tables  furnished  by  manufacturers. 

Table  7-7.     B.t.u.  Required  for  Heating  Air* 

This  table  specifies  the  quantity  of  heat  in  B.  t.  u.  required  to  raise  1  cu.  ft.  of  air  through  any 
given  temper-ill  un-  interval 

Temperature  of  air  in  room,  deg.  fahr. 

*°°  50°  60°  70°  80°  90°  100°  "°°  120°  I30° 


-40° 

1.802 

2.027 

•'  ".v 

2.479 

2.703 

2  928 

3.154 

3.379 

3.601 

3.829 

-30° 

1.540 

1.760 

1^980 

2.200 

2.420 

2.640 

2.860 

3.080 

3.500 

3.520 

-20° 

1.290 

1  .  505 

1.720 

1  .  935 

2.150 

2.365 

2.580 

2.795 

3.010 

3.225 

-10° 

1.051 

1.262 

1.473 

1  681 

1.892 

2.102 

2.311 

2  522 

2.732 

2.943 

0" 

0  822 

1  028 

1  .  23  1 

1  .  439 

1.645 

1  .  851 

2.056 

2  '262 

2.  167 

2.673 

10° 

0.601 

0.805 

1.007 

1.208 

1  .  109 

1.611 

1.812 

2.013 

2.215 

2.416 

20° 

0.393 

0.590 

0.787 

0.981 

1.181 

1.378 

1.575 

1.771 

1.968 

2.165 

30" 

0.192 

0.385 

0.578 

0.770 

0  963 

1.155 

1.845 

1.540 

i  ::!:! 

1  .  925 

10° 

0.000 

0.188 

0.376 

0.561 

0.752 

0.9W 

1.128 

1.316 

1  50  1 

1.692 

50° 

0.000 

0.000 

0.181 

0.367 

0.551 

0.735 

0.918 

1.102 

1.286 

1  .  470 

60° 

0.000 

0.000 

0.000 

0.179 

0.359 

0  538 

0.718 

0.897 

1  .  077 

1  256 

7(1  ' 

(1  (Hill 

(i  nun 

(1  IHKI 

(1  001) 

0.  175 

0.350 

o  :>:.'.-, 

0.700 

0.875 

1  019 

*  !•'.  Schumann's  Manual  of  Healing  and  Ventilation. 

BOILER  HORSEPOWER  REQUIRED:     To  determine  the  boiler  horsepower 
required  for  air  heating,  the  following  formula  can  be  used: 
Cu.ft.permin.X60XA  =  ^  gteam  per  hour 

B 
in  which  A  =   B.t.u.  required  for  heating  1  cu.  ft.  of  air  from  initial  to 

final  temperature  (See  Table  7-7). 
B   =   latent  heat  of  steam 

Ib.  steam  per  hr.  =  boiler  horsepower 


From  the  manufacturers'  tables  the  condensation  rates  per  square  foot 
of  surface  arc  given  for  various  velocities  and  temperatures,  and  it  is  well 
to  check  up  the  above  formula  from  these  given  factors. 

73 


CHAPTER  VIII 


Proportioning  of  Chimneys 

NO  problem  in  the  heating  of  buildings  presents  greater  elements  of 
uncertainty  than  that  of  properly  proportioning  the  chimney. 
In  larger  installations,  such  as  isolated  plants  for  the  production 
of  power,  light  and  heat,  the  conditions  may  usually  be  very  accurately 
determined  in  advance.     By  use  of  the  formula  given  hereafter,  proper 
results  follow  in  almost  every  case. 

A.  Chimneys  for  House- Heating  Boilers 

In  small  plants  and  particularly  residence  heating,  it  is  not  practicable 
to  make  such  accurate  advance  determinations  of  all  the  conditions.  Usually 
the  chimney  is  built  into  the  wall,  thereby  requiring  that  its  cross-section 
must  be  proportioned  to  the  width  of  brick.  Chimneys  so  built  are  usually 
either  smoothly  mortared  on  the  inside  or  lined  with  thin  tile  of  rectangular 
or  circular  cross-section.  The  latter 
gives  such  freedom  from  friction  and 
eddy  currents  and  lessened  surface  for 
loss  of  heat  in  the  gases,  that  a  round 
chimney  lining  will  frequently  give 
fully  as  good  results  as  would  be  ob- 
tained in  the  square  of  brick-work  in 
which  it  is  enclosed. 

The  inclination  to  cut  down  cross- 
sectional  area  to  save  cost  and  space     „ 

„   ,      .,  ,.  .,  ,        Fig.    8-1.     Cross-sections    through    typical    house 

in  the  portion  ol  building  through  chimneys 

which  the  chimney  passes  should  be 

discouraged  as  false  economy.     Once  the  chimney  is  built  into  the  structure, 

increase  of  area  is  practically  impossible,  and  a  chimney  that  is  too  small 


Inside  Area  equals 
80  sq.ins. 


Inside  Area  equals 
188  sq.ins. 


Fig.  8-2.     Seven  bricks  per  course 


Fig.  8-3.     Mine  bricks  per  course 


remains  a  source  of  discomfort  and  waste  during  the  entire  life  of  the  struc- 
ture. Little  is  saved  in  building  an  8J^-in.  by  13-in.  flue  as  compared 
with  a  13-in.  by  18-in.  flue,  the  latter  having  more  than  tw  ice  the  area  and 
more  than  twice  the  capacity,  while  the  bricks  per  course  are  as  9  is  to  7. 
(See  Figures  8-2  and  8-3.) 

To  get  the  greatest  effectiveness,  a  definite  amount  of  draft  must  be 
available.  The  actual  amount  required  varies  widely  for  different  types  of 
commercial  cast-iron  boilers,  and,  unfortunately,  it  is  not  always  possible 
to  know  in  advance  which  make  of  these  boilers  will  be  selected  or  may 
later  be  installed.  It  is,  therefore,  preferable  to  provide  for  excessive  draft 
which  may  be  controlled  by  damper,  rather  than  to  risk  insufficient  draft, 
the  remedying  of  which  is  almost  hopeless. 

For  ascertaining  the  probable  interior  cross-section  of  round  or  rectan- 
gular Hue  linings,  also  unlined  brick  chimneys  necessary  for  average  cast-iron 
healing  boilers  where  height  in  feet  from  combustion  chamber  to  top  of 
chimney  and  maximum  hourly  rate  of  evaporation  in  pounds  of  water  are 
known,  Figures  8-7a  and  8-7b  will  be  found  convenient. 

With  the  maximum  rate  and  height  of  chimney  determined,  enter  the 
table  at  right-hand  column  at  the  determined  hourly  evaporation  rate;  fol- 

Table  8-1.     Dimensions  of  Flue  Linings 

U B J 


a 

, 

( 

t 

1 

^ 

Fig.  8-1 

A 

\ 

Fig. 


Fig.  8-6 


As  manufactured  by 


The  Delaware  Clay  Products  Co. 


W.  S.  Dickey  Clay  Mfg.  Co. 
City,  Mo. 


Robinson  Clay  Products  Co. 


Rectangular 
and  square 

Circular 

Rectangular 
and  square 

Circular 

Rectangular 
and  square 

Circular 

Sq. 

Sq. 

Sq. 

Sq- 

Sq. 

Sq. 

in. 

in. 

in. 

in. 

in. 

in. 

free 

A 

B 

C 

D 

free 

E 

F 

free 

A 

B 

C 

D 

free 

E 

F 

free 

A 

B 

C 

D 

free 

E 

F 

area 

area 

area 

area 

area 

are* 

23 

3^i 

^\^ 

4H 

8H 

28 

6 

IM 

_„, 

3H 

7H 

4H 

8K 

23 

•i'i 

7 

4H 

8H 

28 

6 

7Mi 

36 
47 

:!'- 

II-.', 

4  W 

13 

18 

38 
50 

7 
8 

18 

61 
46 

3« 

7  -H 

i-"" 

8H 

1' 

S'-] 
13 

60 

3^ 

!«S 

13M 

60 

7 
8 

8^ 

39 

6)4 

f,'l 

7H 

7H 

64 

9 

10  f. 

92 

7H 

12H 

13 

47 

4H 

IOH 

6 

12 

64 

9 

10)^ 

52 
80 

BJj 

7ft 

II,7. 

8H 
gU 

13 

78 
113 

10 
12 

14 

145 

127 

"ft 

16  R 

13 
8H 

13 

17H 

125 

12  Mi 

UV 

33 

52.5 

?H 

T% 

8H 

8H 

78 
113 

10 
12 

12 

14 

110 
129 

llj| 

iiS 

13 

18 
13 

176 
254 

15 
18 

SB 

202 
270 

l«i 

if.    . 
16A 

1» 

i?B 

80 
104 

'•',' 

HH 
16 

% 

13 

18 

176 
254 

15 

18 

W& 

188 

ll\4 

16H 

13 

18 

314 

20 

22H 

291 

19^ 

21  H 

127 

ll^i 

11H 

13 

13 

314 

20 

23 

256 

10 

16 

18 

18 

ixn 

•1-1 

-'•"•  '  i 

169 

]!)'', 

15^ 

13 

18 

346 

21 

1  .",  J 

24 

-~'i 

I  '.''.' 

25  ft 

27H 

240 

15H 

15H 

18 

18 

380 

22 

452 

24 

27 

572 

27 

707 

30 

35 

855 

33 

1018 

36 

Mole.     All  dimftnsioii!i  are  in  inches  and  subject  to  slight  variation 


TYPES  OF  CHIMNEY  CONSTRUCTION 
Rectangular  Tile     Circular  Tile        Rouohji  ick 


Fig.  8-7a 


30       40      50       60       70      SO       90      100 

FEET  IN  HEIGHT  BETWEEN  COMBUSTION  CHAMBER 

AND  TOP  OF  CHIMNEY 


78 


TYPES  OF  CHIMNEY  CONSTRUCTION 

Rectangular  Tile     Circular  Tile         Rough  Blick 


30       40       50      00       70      80      90      100 

FEET  IN  HEIGHT  BETWEEN  COMBUSTION  CHAMBER 

AND  TOP  OF  CHIMNEY 


GOO 


500 


Fig.  8-7b— Probable  capacities  of  chimneys  of  different  forms,  sizes  and  heights  to  produce 
proper  draft  for  average  cast-iron  boiler  of  up-draft  type  using  anthracite  coal 


horizontally  to  left  to  intersection  of  vertical  line  representing  given 
height,  then  downward  along  the  curve  to  its  left  end,  then  follow  a  hori- 
zontal line  to  left ;  the  interior  cross-sections  of  linings  and  rough  brick 
above  the  horizontal  should  be  ample  under  usual  conditions. 

77 


When  desiring  to  ascertain  probable  capacity  of  a  chimney  of  known 
dimensions  and  construction,  the  chart  is  read  in  reverse  order. 

Dotted  lines  on  Fig.  8-7b  indicate  that  for  11800  Ib.  evaporation  per 
hr.  and  60-ft.  chimney  height,  a  22-in.  diameter,  or  16  by  28-in.  tile  lining 
should  be  proper,  or  that  20  by  24-in.  rough  brick  would  be  ample. 

It  must,  however,  be  borne  in  mind  that  the  location  of  the  building  in 
relation  to  topography  and  surrounding  structures  may  render  a  chimney 
absolutely  inefficient,  while  another  similar  in  every  respect  of  height  and 
cross-section,  used  for  similar  boiler  and  fuel,  but  favorably  located,  will  be 
able  to  produce  a  superabundance  of  draft;  also  that  the  resistance  due  to 
thickness  of  coal  bed,  character  and  quality  of  fuel  as  well  as  resistance  be- 
tween the  combustion  chamber  and  chimney,  vary  in  different  makes  of 
boilers  having  similar  ratings,  and  that  these  resistances  form  a  large  part 
of  the  total  head  for  which  chimneys  are  required. 

The  chimney  problem  should  be  presented  to  the  boiler  manufacturer 
for  his  study  and  recommendation. 

B.    Chimneys  and  Draft  for  Power  Boilers* 

The  height  and  diameter  of  a  properly  designed  chimney  depend  upon 
the  amount  of  fuel  to  be  burned,  the  design  of  the  flue,  with  its  arrange- 
ment relative  to  the  boiler  or  boilers,  and  the  altitude  of  the  plant  above  sea 
level.  There  are  so  many  factors  involved  that  as  yet  there  has  been  pro- 
duced no  formula  which  is  satisfactory  in  taking  them  all  into  consideration 
and  the  methods  used  for  determining  stack  sizes  are  largely  empirical.  In 
this  chapter  a  method  sufficiently  comprehensive  and  accurate  to  cover  all 
practical  cases  will  be  developed  and  illustrated. 

DRAFT  is  the  difference  in  pressure  available  for  producing  a  flow  of  the 
gases.  If  the  gases  within  a  stack  be  heated,  each  cubic  foot  will  expand, 
and  the  weight  of  the  expanded  gas  per  cubic  foot  will  be  less  than  that  of  a 
cubic  foot  of  the  cold  air  outside  the  chimney.  Therefore,  the  unit  pressure 
at  the  stack  base  due  to  the  weight  of  the  column  of  heated  gas  will  be  less 
than  that  due  to  a  column  of  cold  air.  This  difference  in  pressure,  like  the 
difference  in  head  of  water,  will  cause  a  flow  of  the  gases  into  the  base  of  the 
stack.  In  its  passage  to  the  stack  the  cold  air  must  pass  through  the  furnace 
or  furnaces  of  the  boilers  connected  to  it,  and  it  in  turn  becomes  heated. 
This  newly  heated  gas  also  rises  in  the  stack  and  the  action  is  continuous. 

The  intensity  of  the  draft,  or  difference  in  pressure,  is  usually  measured 
in  inches  of  water.     Assuming  an  atmospheric  temperature  of  62   deg. 
fahr.  and  the  temperature  of  the  gases  in  the  chimney  as  500  deg.  fahr., 
and,  neglecting  for  the  moment  the  difference  in  density  between  the  chim- 
ney gases  and  the  air,  the  difference  between  the  weights  of  the  external  air 
and  the  internal  flue  gases  per  cubic  foot  is  0.0347  Ib.,  obtained  as  follows: 
Weight  of  a  cubic  foot  of  air  at    62  deg.  fahr.  =  0.0761  Ib. 
Weight  of  a  cubic  foot  of  air  at  500  deg.  fahr.  =  0.0414  Ib. 

Difference  =  0.0347  Ib. 

*  Reprinted  from  Steam  by  permission  of  Babcock  &  Wilcox  Co. 

78 


Therefore,  a  chimney  100  ft.  high,  assumed  for  the  purpose  of  illustration 
to  be  suspended  in  the  air,  would  have  a  pressure  exerted  on  each  square 
foot  of  its  cross-sectional  area  at  its  base  of  0.0347  x  100  =  3.47  Ib.  As 
a  cubic  Coot  of  water  at  62  deg.  fahr.  weighs  62.32  Ib.,  an  inch  of  water 
would  exert  a  pressure  of  62.32-^12  =  5.193  Ib.  per  sq.  ft.  The  100-ft. 
slack  would,  therefore,  under  the  above  temperature  conditions,  show  a 
draft  of  3.  1  7  -j-  5.  193  or  approximately  0.67  in.  of  water. 

The  method  best  suited  for  determining  the  proper  proportion  of  stacks 
and  flues  is  dependent  upon  the  principle  that  if  the  cross-sectional  area 
of  the  slack  is  sufficiently  large  for  the  volume  of  gases  to  be  handled,  the 
intensity  of  the  draft  will  depend  directly  upon  the  height;  therefore,  the 
method  of  procedure  is  as  follows: 

(1)  Select  a  stack  of  height  to  produce  the  draft  required  by  the  partic- 
ular character  of  fuel  and  amount  burned  per  square  foot  of  grate  surface 

(2)  Determine  the  cross-sectional  area  necessary  to  handle  the  gases 
without  undue  frictional  losses. 

The  application  of  these  rules  follows: 

DRAFT  FORMULA:  The  force  or  intensity  of  the  draft,  not  allowing  for 
difference  in  density  of  air  and  of  the  flue  gases,  is  given  by  the  formula: 

D  =  0.52  Hxp(I—  I)  (Formula  8-1} 

in  which  *•  *  * 

D  =  draft  produced,  measured  in  inches  of  water, 

H  =  height  of  top  of  stack  above  grate  bars  in  feet, 

P    =  atmospheric  pressure  in  pounds  per  square  inch, 

T   =  absolute  atmospheric  temperature, 

Ti  =  absolute  temperature  of  stack  gases. 

In  this  formula  no  account  is  taken  of  the  density  of  the  flue  gases,  it 
being  assumed  that  it  is  the  same  as  that  of  air.  Any  error  arising  from  this 
assumption  is  negligible  in  practice,  as  a  factor  of  correction  is  applied  in 
using  the  formula  to  cover  the  difference  between  the  theoretical  figures  and 
those  corresponding  to  actual  operating  conditions. 

The  force  of  draft  at  sea  level  (which  corresponds  to  an  atmospheric  pres- 
sure of  14.7  Ib.  per  sq.  in.)  produced  by  a  chimney  100  ft.  high  with  the 
temperature  of  the  air  at  60  deg.  fahr.  and  that  of  the  flue  gases  at  500  deg. 
fahr.  is,  /  1  1  \ 

D  =  0.52  x  100  x  14.7     i-i     =  0.67 


Under  the  same  temperature  conditions  this  chimney  at  an  atmospheric 
pressure  of  10  Ib.  per  sq.  in.  (which  corresponds  to  an  altitude  of  about 
10000  ft.  above  sea  level)  would  produce  a  draft  of, 


D  =  0.52  x  100  x  10  -  -  0.45 

For  using  this  formula  it  is  handy  to  tabulate  values  of  the  product, 
0.52  x  14.7  (  1,  _  ^ 


7» 


which  we  will  call  K,  for  various  values  of  Ti.     With  these  values  calculated 
for  assumed  atmospheric  temperature  and  pressure,  Formula  8-1  becomes, 

D  =  K  H.  (Formula  8-2) 

For  average  conditions  the  atmospheric  pressure  may  be  considered 
14.7  Ib.  per  sq.  in.,  and  the  temperature  60  deg.  fahr.  For  these  values 
and  various  stack  temperatures  K  becomes: 

Temperature  of  slack  gases  Constant  K 

750 ' 0084 

700 0081 

650 0078 

600 0075 

550 0071 

500 0067 

450 0063 

400 0058 

350 0053 

DRAFT  LOSSES:  The  intensity  of  the  draft  as  determined  by  the  above 
formula  is  theoretical  and  can  never  be  observed  with  a  draft  gauge  or  any 
recording  device.  However,  if  the  ashpit  doors  of  the  boiler  are  closed  and 
there  is  no  perceptible  leakage  of  air  through  the  boiler  setting  or  flue,  the 
draft  measured  at  the  stack  base  will  be  approximately  the  same  as  the 
theoretical  draft.  The  difference  existing  at  other  times  represents  the  pres- 
sure necessary  to  force  the  gases  through  the  stack  against  their  own  inertia 
and  the  friction  against  the  sides.  This  difference  will  increase  with  the 
velocity  of  the  gases.  With  the  ashpit  doors  closed  the  volume  of  gases 
passing  to  the  stack  is  a  minimum  and  the  maximum  force  of  draft  will  be 
shown  by  a  gauge. 

As  draft  measurements  are  taken  along  the  path  of  the  gases,  the  read- 
ings grow  less  as  the  points  at  which  they  are  taken  are  farther  from  the 
stack,  until  in  the  boiler  ashpit,  with  the  ashpit  doors  open  for  freely  admit- 
ting the  air,  there  is  little  or  no  perceptible  rise  in  the  water  of  the  gauge. 
The  breeching,  the  boiler  damper,  the  baffles  and  the  tubes,  and  the  coal  on 
the  grates  all  retard  the  passage  of  the  gases,  and  the  draft  from  the  chimney 
is  required  to  overcome  the  resistance  offered  by  the  various  factors.  The 
draft  at  the  rear  of  the  boiler  setting  where  connection  is  made  to  the  stack 
or  flue  may  be  0.5-in.,  while  in  the  furnace  directly  over  the  fire  it  may 
not  be  over,  say,  0.15-in.,  the  difference  being  the  draft  required  to  over- 
come the  resistance  offered  in  forcing  the  gases  through  the  tubes  and 
around  the  baffling. 

One  of  the  most  important  factors  to  be  considered  in  designing  a  stack 
is  the  pressure  required  to  force  the  air  for  combustion  through  the  bed  of 
fuel  on  the  grates.  This  pressure  will  vary  with  the  nature  of  the  fuel 
used,  and  in  many  instances  will  be  a  large  percentage  of  the  total  draft. 
In  the  case  of  natural  draft,  its  measure  is  found  directly  by  noting  the 
draft  in  the  furnace,  for  with  properly  designed  ashpit  doors  it  is  evident 
that  the  pressure  under  the  grates  will  not  differ  sensibly  from  atmospheric 
pressure. 

Loss  IN  STACK:  The  difference  between  the  theoretical  draft  as  de- 
termined by  Formula  8-1  and  the  amount  lost  by  friction  in  the  stack 
proper,  is  the  available  draft,  or  that  which  the  draft  gauge  indicates  when 

80 


connected  to  the  base  of  the  stack.  The  sum  of  the  losses  of  draft  in  the 
flue,  boiler  and  furnace  must  be  equivalent  to  the  available  draft,  and  as 
these  quantities  can  be  determined  from  record  of  experiments,  the  problem 
of  designing  a  stack  becomes  one  of  proportioning  it  to  produce  a  certain 
available  draft. 

The  loss  in  the  stack  due  to  friction  of  the  gases  can  be  calculated  from 
the  following  formula:  fwVH 

AD=^fi  (Formula  8-3) 

in  which 

A  D  =  draft  loss  in  inches  of  water, 
W  =  weight  of  gas  in  pounds  passing  per  second, 
C  =  perimeter  of  stack  in  feet, 
H  =  height  of  stack  in  feet, 

/  =  a  constant  with  the  following  values  at  sea  level: 
.0015  for  steel  stacks,  temperature  of  gases  600  deg.  fahr. 
.0011  for  steel  stacks,  temperature  of  gases  350  deg.  fahr. 
.0020  for  brick  or  brick-lined  stacks,  temperature  of  gases  600  deg.  fahr. 
.0015  for  brick  or  brick-lined  stacks,  temperature  of  gases  350  deg.  fahr. 
A  =  area  of  stack  in  square  feet. 

This  formula  can  also  be  used  for  calculating  the  frictional  losses  for 
flues,  in  which  case,  C  =  the  perimeter  of  the  flue  in  feet,  H  =  the  length  of 
the  flue  in  feet,  the  other  values  being  the  same  as  for  stacks. 

The  available  draft  is  equal  to  the  difference  between  the  theoretical 
draft  from  Formula  8-2  and  the  loss  from  Formula  8-3,  hence: 

fW'CH 
rf1  =  available  draft  =  KH  —  - — -r^—  (Formula  8-4) 

A. 

Table  8-2  gives  the  available  draft  in  inches  that  a  stack  100  ft.  high 
will  produce  when  serving  different  horsepowers  of  boilers  with  the  methods 
of  calculation  for  other  heights. 

HEIGHT  AND  DIAMETER  OF  STACKS:  From  Formula  8-4,  it  becomes 
evident  that  a  stack  of  certain  diameter,  if  it  be  increased  in  height,  will 
produce  the  same  available  draft  as  one  of  larger  diameter,  the  additional 
height  being  required  to  overcome  the  added  frictional  loss.  It  follows  that 
among  the  various  stacks  that  would  meet  the  requirements  of  a  particular 
case  there  must  be  one  which  can  be  constructed  more  cheaply  than  the 
others.  It  has  been  determined  from  relation  of  stack  costs  to  diameters 
and  heights,  in  connection  with  the  formula  for  available  draft,  that  the 
minimum  cost  stack  has  a  diameter  dependent  solely  upon  the  horsepower 
of  the  boilers  served,  and  a  height  proportional  to  available  draft  required. 

Assuming  120  Ib.  of  flue  gas  per  hr.  for  each  boiler  horsepower,  which 
provides  for  ordinary  overloads  and  use  of  poor  coal,  the  method  stated  gives: 

For  unlined  steel  stack — diameter  in  inches  =  1.68  (hp.) '.    (Formula  8-5.) 
For  masonry  lined  stack — diameter  in  inches  =  4.92  (hp.)  *.  (Formula  8-6.) 

In  both  of  these  formulae,  hp.  =  the  rated  horsepower  of  the  boiler. 
From  this  formula  the  curve,  Figure  8-8,  has  been  calculated  and  from 
it  the  stack  diameter  for  any  boiler  horsepower  can  be  selected. 

81 


Table  8-2.     Available  Draft 

Calculated  for  100-ft.  stack  of  different  diameters,  assuming  stack  temperature  of  500  deg.  fahr.  and  100  Ib. 
of  gas  per  hp.     For  other  heights  of  stack  multiply  draft  by  height  -=-  100 


Horse- 
power 

Diameter  of  stack  in  inches 

Horse 
power 

Diameter  of  stack  in  inches 

36 

42 

48 

54 

60 

66 

72 

78 

84 

90 

96 

102 

108 

114 

120 

90 

96 

102 

108 

114 

120 

132 

144 

100 

64 

2600 

47 

.53 

.56 

59 

.61 

.62 

64 

.65 

200 

55 

62 

2700 

45 

.52 

.55 

58 

.60 

.62 

64 

.65 

300 

41 

55 

61 

2800 

44 

.50 

.55 

58 

.60 

.61 

64 

.65 

400 

21 

46 

56 

61 

2900 

42 

.49 

.54 

57 

.59 

.61 

.63 

.65 

500 

34 

50 

57 

.61 

3000 

40 

.48 

.53 

.56 

.59 

.61 

.63 

.64 

600 

19 

42 

53 

.59 

3100 

38 

.47 

.52 

.56 

.58 

.60 

.63 

.64 

700 

.34 

48 

.56 

.60 

63 

3200 

.45 

.51 

.55 

.58 

60 

.63 

.64 

800 

.23 

43 

.52 

.58 

61 

.63 

3300 

.44 

.50 

.54 

.57 

.59 

.62 

.64 

900 

36 

.49 

.56 

60 

.62 

.64 

3400 

.42 

49 

.53 

.56 

.59 

.62 

.64 

1000 

.29 

.45 

.53 

58 

.61 

.63 

.64 

3500 

.40 

.48 

.52 

.56 

.58 

.62 

.64 

1100 

.40 

.50 

.56 

.60 

.62 

.63 

.64 

3600 

.47 

.52 

.55 

.58 

.61 

.63 

1200 

.35 

.47 

.54 

.58 

.61 

.63 

.64 

.65 

3700 

.45 

.51 

.55 

.57 

.61 

.63 

1300 

.29 

.44 

.52 

.57 

.60 

.62 

.63 

.64 

.65 

3800 

.44 

.  .-><> 

.54 

.57 

.61 

.63 

1400 

.40 

.49 

.55 

.59 

.61 

.63 

.64 

.65 

.65 

3900 

.43 

.49 

.53 

.56 

.60 

.63 

1500 

.36 

.47 

.53 

.58 

.60 

.62 

.63 

.64 

.65 

.65 

4000 

.42 

.48 

.52 

.56 

.60 

.62 

1600 

.31 

.43 

.52 

.56 

.59 

.62 

.63 

.64 

.65 

.65 

4100 

.40 

.47 

.52 

.55 

.60 

.62 

1700 

.41 

.50 

.55 

.58 

.61 

.62 

.64 

.64 

.65 

4200 

.39 

.46 

.51 

.55 

.59 

.62 

1800 

.37 

.47 

.54 

.57 

.60 

.62 

.63 

.64 

.65 

4300 

.45 

.50 

.54 

.59 

.62 

1900 

.34 

.45 

.52 

.56 

.59 

.61 

.63 

.64 

.64 

4400 

.44 

.49 

.53 

.59 

.62 

2000 

.43 

.50 

.55 

.59 

.61 

.62 

.63 

.64 

4500 

42 

.49 

.53 

.58 

.61 

2100 

.40 

.49 

.54 

.58 

.60 

.62 

.63 

.64 

4600 

'.42 

.48 

.52 

.58 

.61 

2200 

.38 

.47 

.53 

.57 

.59 

.61 

.62 

.64 

4700 

.41 

.47 

.51 

.57 

.61 

2300 

.35 

.45 

.52 

.56 

.59 

.61 

.62 

.63 

4800 

.40 

.46 

.51 

.57 

.60 

2400 

.32 

.43 

.50 

.55 

.58 

.60 

.62 

.63 

4900 

.45 

.50 

.57 

.60 

2500 

.41 

.49 

.54 

.57 

.60 

.61 

.63 

5000 

.44 

.49 

.56 

.60 

For  other  stack  temperature  add  or  deduct  before  multiplying  by 


e' 


as  follows:* 


For  750  deg.  fahr. 

add  .  17  in. 
For  700  deg.  fahr. 

add  .  14  in. 


For  650  deg.  fahr. 

add  .11  in. 
For  600  deg.  fahr. 

add  .08  in. 


For  550  deg.  fahr. 

add  .  04  in. 
For  450  deg.  fahr. 

deduct  .  04  in 


For  400  deg.  fahr. 

deduct  .  09  in. 
For  350  deg.  fahr. 

deduct  .  14  in. 


*  Results  secured  by  this  method  will  be  approximately  correct 


For  stoker  practice  where  a  large  stack  serves  a  number  of  boilers,  the 
area  is  usually  made  about  one-third  more  than  the  above  rules  call  for, 
which  allows  for  leakage  of  air  through  the  setting  of  any  idle  boilers,  ir- 
regularities in  operating  conditions,  etc. 

Stacks  with  diameters  determined  as  above  will  give  an  available 
draft  which  bears  a  constant  ratio  of  the  theoretical  draft,  and  allowing  for 
the  cooling  of  the  gases  in  their  passage  upward  through  the  stack,  this 
ratio  is  0.8.  Using  this  factor  in  Formula  8-2,  and  transposing,  the  height  of 
the  chimney  becomes,  ^ 

(Formula  8-7} 


H  = 


.8K 


Where  H  =  height  of  stack  in  feet  above  the  level  of  the  grates, 
dl  =  available  draft  required, 
K  =  constant  as  in  Formula  8-2. 


82 


120 


^  70 


0   200  400  GOO  800  1000  1200  1400  1COO  1800  2000  2200  2400  2000  2800  3000  3200  3400  3600  3800  4000 

Horsepower  of  Boilers 

Fig.  8-8.     Diameter  of  stacks  and  horsepower  they  will  serve 
Computed  from  Formula  (8-5).     For  brick  or  brick-lined  stacks  increase  the  dimneter  6  per  cent 

LOSSES  IN  FLUES:  The  loss  of  draft  in  straight  flues  due  to  friction  and 
inertia  can  be  calculated  approximately  from  Formula  8-3,  which  was  given 
for  loss  in  stacks.  It  is  to  be  borne  in  mind  that  C  in  this  formula  is  the 
actual  perimeter  of  the  flue  and  is  least,  relative  to  the  cross-sectional  area, 
when  the  section  is  a  circle,  is  greater  for  a  square  section,  and  greatest  for  a 
rectangular  section.  The  retarding  effect  of  a  square  flue  is  12  per  cent 
greater  than  that  of  a  circular  flue  of  the  same  area  and  that  of  a  rectangular 
with  sides  as  1  and  1J^,  15  per  cent  greater.  The  greater  resistance  of  the 
more  or  less  uneven  brick  or  concrete  flue  is  provided  for  in  the  value  of  the 
constants  given  for  Formula  8-3.  Both  steel  and  brick  flues  should  be  short 
and  should  have  as  near  a  circular  or  square  cross-section  as  possible. 
\brupt  turns  are  to  be  avoided,  but  as  long  easy  sweeps  require  valuable 
space,  it  is  often  desirable  to  increase  the  height  of  the  stack  rather  than  to 
take  up  added  space  in  the  boiler  room.  Short  right-angle  turns  reduce 
the  draft  by  an  amount  which  can  be  roughly  approximated  as  equal  to  0.05- 
in.  for  each  turn.  The  turns  which  the  gases  make  in  leaving  the  damper 
box  of  a  boiler,  in  entering  a  horizontal  flue  and  in  turning  up  into  a  stack 
should  always  be  considered.  The  cross-sectional  areas  of  the  passages 
leading  from  the  boilers  to  the  stack  should  be  of  ample  size  to  provide  against 
undue  frictional  loss.  It  is  poor  economy  to  restrict  the  size  of  the  Hue  and 
thus  make  additional  stack  height  necessary  to  o\ercome  the  added  friction. 
The  general  pract  ice  is  to  make  flue  areas  the  same  or  slightly  larger  I  lian  that 
of  the  stack;  these  should  be,  preferably,  at  least  20  per  cent  greater,  and 
a  safe  rule  to  follow  in  figuring  flue  areas  is  to  allow  35  sq.  ft.  per  1000 

83 


horsepower.  It  is  unnecessary  to  maintain  the  same  size  of  flue  the  entire 
distance  behind  a  row  of  boilers,  and  the  areas  at  any  point  may  be  made 
proportional  to  the  volume  of  gases  that  will  pass  that  point.  That  is,  the 
areas  may  be  reduced  as  connections  to  various  boilers  are  passed. 

With  circular  steel  flues  of  approximately  the  same  size  as  the  stacks,  or 
reduced  proportionally  to  the  volume  of  gases  they  will  handle,  a  convenient 
rule  is  to  allow  0.1-in.  draft  loss  per  100  ft.  of  flue  length  and  0.05-in.  for 
each  right-angle  turn.  These  figures  are  also  good  for  square  or  rectangular 
steel  flues  with  areas  sufficient  to  provide  against  excessive  frictional  loss. 
For  losses  in  brick  or  concrete  flues,  these  figures  should  be  doubled. 

Underground  flues  are  less  desirable  than  overhead  or  rear  flues  for  the 
reason  that  in  most  instances  the  gases  will  have  to  make  more  turns  where 
underground  flues  are  used  and  because  the  cross-sectional  area  of  such 
flues  will  oftentimes  be  decreased  on  account  of  an  accumulation  of  dirt  or 
water  which  it  may  be  impossible  to  remove. 

In  tall  buildings,  such  as  office  buildings,  it  is  frequently  necessary  in 
order  to  carry  spent  gases  above  the  roofs  to  install  a  stack  the  height  of 
which  is  out  of  all  proportion  to  the  requirements  of  the  boilers.  In  such 
cases  it  is  permissible  to  decrease  the  diameter  of  a  stack,  but  care  must  be 
taken  that  this  decrease  is  not  sufficient  to  cause  a  frictional  loss  in  the  stack 
as  great  as  the  added  draft  intensity  due  to  the  increase  in  height,  which 
local  conditions  make  necessary. 

In  such  cases  also  the  fact  that  the  stack  diameter  is  permissibly 
decreased  is  no  reason  why  flue  sizes  connecting  to  the  stack  should  be 
decreased.  These  should  still  be  figured  in  proportion  to  the  area  of  the  stack 
that  would  be  furnished  under  ordinary  conditions  or  with  an  allowance  of 
35  sq.  ft.  per  1000  horsepower,  even  though  the  cross-sectional  area  appears 
out  of  proportion  to  the  stack  area. 

Loss  IN  BOILERS:  In  calculating  the  available  draft  of  a  chimney,  120 
Ib.  per  hr.  has  been  used  as  the  weight  of  the  gases  per  boiler  horse- 
power. This  covers  an  overload  of  the  boiler  to  an  extent  of  50  per  cent  and 
provides  for  the  use  of  poor  coal.  The  loss  in  draft  through  a  boiler  proper 
will  depend  upon  its  type  and  baffling  and  will  increase  with  the  per  cent 
of  rating  at  which  it  is  run.  No  figures  can  be  given  which  will  cover  all 
conditions,  but  for  approximate  use  in  figuring  the  available  draft  necessary 
it  may  be  assumed  that  the  loss  through  a  boiler  will  be  0.25-in.  where  the 
boiler  is  run  at  rating,  0.40-in.  where  it  is  run  at  150  per  cent  of  its  rated 
capacity,  and  0.70-in.  where  it  is  run  at  200  per  cent  of  its  rated  capacity. 

Loss  IN  FURNACE:  The  draft  loss  in  the  furnace  or  through  the  fuel 
bed  varies  between  wide  limits.  The  air  necessary  for  combustion  must 
pass  through  the  interstices  of  the  coal  on  the  grate.  Where  these  are 
large,  as  in  the  case  with  broken  coal,  but  little  pressure  is  required  to  force 
the  air  through  the  bed;  but  if  they  are  small,  as  with  bituminous  slack  or 
small  sizes  of  anthracite,  a  much  greater  pressure  is  needed.  If  the  draft 
is  insufficient  the  coal  will  accumulate  on  the  grates  and  a  dead,  smoky  fire 
will  result  with  the  accompanying  poor  combustion;  if  the  draft  is  too  great, 
the  coal  may  be  rapidly  consumed  on  certain  portions  of  the  grate,  leaving 

84 


15  20  25  30  35 

Pounds  of  Coal  Burned  per  Sq.  Ft.  of  Grate  Surface  per  Hour 


10 


Fig.  8-9.     Draft  required  at  different  combustion  rates  for  various  kinds  of  coal 

the  fire  thin  in  spots  and  a  portion  of  the  grates  uncovered  with  the  resulting 
losses  due  to  an  excessive  amount  of  air. 

DRAFT  REQUIRED  FOR  DIFFERENT  FUELS:  For  every  kind  of  fuel  and 
rate  of  combustion  there  is  a  certain  draft  with  which  the  best  general  results 
are  obtained.  A  comparatively  light  draft  is  best  with  the  free-burning 
bituminous  coals  and  the  amount  to  use  increases  as  the  percentage  of 
volatile  matter  diminishes  and  the  fixed  carbon  increases,  being  highest  for 
the  small  sizes  of  anthracites.  Numerous  other  factors,  such  as  the  thick- 
ness of  fires,  the  percentage  of  ash  and  the  air  spaces  in  the  grates  bear  directly 
on  this  question  of  the  draft  best  suited  to  a  given  combustion  rate.  The 
effect  of  these  factors  can  only  be  found  by  experiment.  It  is  almost  im- 
possible to  show  by  one  set  of  curves  the  furnace  draft  required  at  various 
rates  of  combustion  for  all  of  the  different  conditions  of  fuel,  etc.,  that  may 
be  met.  The  curves  in  Figure  8-9,  however,  give  the  furnace  draft  necessary 
to  burn  various  kinds  of  coal  at  the  combustion  rates  indicated  by  the  abscis- 
sae, for  a  general  set  of  conditions.  These  curves  have  been  plotted  from 
the  records  of  numerous  tests  and  allow  a  safe  margin  for  economically 
burning  coals  of  the  kinds  noted. 

RATE  OF  COMBUSTION:  The  amount  of  coal  which  can  be  burned  per 
hour  per  square  foot  of  grate  surface  is  governed  by  the  character  of  the  coal 
and  the  draft  available.  Where  the  boiler  and  grate  are  properly  propor- 


tioned,  the  efficiency  will  be  practically  the  same,  within  reasonable  limits, 
for  different  rates  of  combustion.  The  area  of  the  grate,  and  the  ratio  of 
this  area  to  the  boiler  heating  surface  will  depend  upon  the  nature  of  the  fuel 
to  be  burned,  and  the  stack  should  be  so  designed  as  to  give  a  draft  sufficient 
to  burn  the  maximum  amount  of  fuel  per  square  foot  of  grate  surface  cor- 
responding to  the  maximum  evaporative  requirements  of  the  boiler. 

SOLUTION  OF  A  PROBLEM  :  The  stack  diameter  can  be  determined  from 
the  curve,  Figure  8-8.  The  height  can  be  determined  by  adding  the  draft 
losses  in  the  furnace,  through  the  boiler  and  flues,  and  computing  from 
Formula  8-7  the  height  necessary  to  give  this  draft. 

Example:  Proportion  a  stack  for  boilers  rated  at  2000  horsepower, 
equipped  with  stokers,  and  burning  bituminous  coal  that  will  evaporate 
8  Ib.  of  water  from  and  at  212  deg.  fahr.  per  Ib.  of  fuel;  the  ratio  of  boiler 
heating  surface  to  grate  surface  being  50:  1;  the  flues  being  100  ft.  long  and 
containing  two  right-angle  turns;  the  stack  to  be  able  to  handle  overloads 
of  50  per  cent;  and  the  rated  horsepower  of  the  boilers  based  on  10  sq.  ft. 
of  heating  surface  per  horsepower. 

The  atmospheric  temperature  may  be  assumed  as  60  deg.  fahr.  and 
the  flue  temperatures  at  the  maximum  overload  as  550  deg.  fahr.  The 

grate  surface  equals  400  sq.  ft.     The  total  coal  burned  at  rating  =  --  ^— 
=  8624  Ib.     The  coal  per  square  foot  of  grate  surface  per  hour  at  rating 


-  -   22  Ih 

400          ^  1D' 

For  50  per  cent  overload  the  combustion  rate  will  be  approximately 
60  per  cent  greater  than  this,  or  1.60  x  22  =  35  Ib.  per  sq.  ft.  of  grate 
surface  per  hr.  The  furnace  draft  required  for  the  combustion  rate,  from 
the  curve,  Figure  8-9,  is  0.6-in.  The  loss  in  the  boiler  will  be  0.4-in.,  in  the 
flue  0.1  in.,  and  in  the  turns  2  x  0.05  =  0.1-in.  The  available  draft  required 
at  the  base  of  the  stack  is,  therefore, 

Inches 

Boiler  ..................................................   0.4 

Furnace  ................................................  0.6 

Flues.  ...............................................  ..0.1 

Turns  ..................................................  0.1 

Total  ..............................................  T2 

Since  the  available  draft  is  80  per  cent  of  the  theoretical  draft,  this  draft 
due  to  the  height  required  is  1.2  -4-  0.8  =  1.5  inches. 

The  chimney  constant  for  temperatures  of  60  deg.  fahr.  and  550  deg. 
fahr.  is  0.0071  and  from  Formula  8-7, 

H  =       =  2U  ft- 


Its  diameter  from  curve  in  Figure  8-7  is  96  in.  if  unlined,  and  102  in. 
inside  if  lined  with  masonry.  The  cross-sectional  area  of  the  flue  should 
be  approximately  70  sq.  ft.  at  the  point  where  the  total  amount  of  gas  is  to 
be  handled,  tapering  to  the  boiler  farthest  from  the  stack  to  a  size  which 
will  depend  upon  the  size  of  the  boiler  units  used. 

86 


CORRECTION  IN  STACK  SIZES  FOR  ALTITUDES:  It  has  been  assumed 
that  a  stack  height  for  altitude  will  be  increased  inversely  as  the  ratio  of 
barometric  pressure  at  the  altitude  to  that  at  sea  level,  and  that  the  stack 
diameter  increases  inversely  as  the  two-fifths  power  of  this  ratio.  This 
relation  assumes  a  constant  draft  measured  in  inches  of  water  at  base  of 
stack  for  a  given  rate  of  boiler  operation,  regardless  of  altitude. 

If  the  assumption  be  made  that  boilers,  flues  and  furnaces  remain  the 
same,  and  further  that  the  increased  velocity  of  a  given  weight  of  air  passing 
through  the  furnace  at  a  higher  altitude  would  have  no  effect  on  the  com- 
bustion, the  theory  has  been  advanced*  that  a  different  law  applies. 

Under  the  above  assumptions,  whenever  a  stack  is  working  at  its  maxi- 
mum capacity  at  any  altitude,  the  entire  draft  is  utilized  in  overcoming  the 
various  resistances,  each  of  which  is  proportional  to  the  square  of  the  velocity 
of  the  .gases.  Since  boiler  areas  are  fixed,  all  velocities  may  be  related  to  a 
common  velocity,  say  that  within  the  stack,  and  all  resistances  may,  there- 
fore, be  expressed  as  proportional  to  the  square  of  the  chimney  velocity. 
The  total  resistance  to  flow,  in  terms  of  velocity  head,  may  be  expressed  in 
terms  of  weight  of  a  column  of  external  air,  the  numerical  value  of  such  head 
being  independent  of  the  barometric  pressure.  Likewise  the  draft  of  a  stack, 
expressed  in  height  of  column  of  external  air,  will  be  numerically  independent 
of  the  barometric  pressure.  It  is  evident,  therefore,  that  if  a  given  boiler 
plant,  with  its  stack  operated  with  a  fixed  fuel,  be  transplanted  from  sea 
level  to  an  altitude,  assuming  the  temperatures  remain  constant,  the  total 
draft  head  measured  in  height  of  column  of  external  air  will  be  numerically 
constant.  The  velocity  of  chimney  gases  will,  therefore,  remain  the  same  at 
altitude  as  at  sea  level  and  the  weight  of  gases  flowing  per  second  with  a 
fixed  velocity  will  be  proportional  to  the  atmospheric  density  or  inversely 
proportional  to  the  normal  barometric  pressure. 

To  develop  a  given  horsepower  requires  a  constant  weight  of  chimney 
gas  and  air  for  combustion.  Hence,  as  altitude  is  increased,  the  density  is 
decreased  and,  for  the  assumptions  given,  the  velocity  through  furnace, 
boiler  passes,  breeching  and  flues  must  be  correspondingly  greater  at  altitude 
than  at  sea  level.  The  mean  velocity,  therefore,  for  given  boiler  horsepower 
and  constant  weight  of  gases  will  be  inversely  proportional  to  the  barometric 
pressure  and  the  velocity  head  measured  in  column  of  external  air  will  be 
inversely  proportional  to  the  square  of  the  barometric  pressure. 

For  stacks  operating  at  altitude  it  is  necessary  not  only  to  increase  the 
height  but  also  the  diameter,  as  there  is  an  added  resistance  within  the  stack 
due  to  the  added  friction  from  the  additional  height.  This  frictional  loss 
can  be  compensated  by  a  suitable  increase  in  the  diameter  and  when  so  com- 
pensated, the  chimney  height  would  have  to  be  increased  at  a  ratio  inversely 
proportional  to  the  square  of  the  normal  barometric  pressure. 

In  designing  a  boiler  for  high  altitudes,  as  already  stated,  the  assumption 
is  usually  made  that  a  given  grade  of  fuel  will  require  the  same  draft  measured 
in  inches  of  water  at  the  boiler  damper  as  at  sea  level,  and  this  leads  to  mak- 
ing the  stack  height  inversely  as  the  barometric  pressures,  instead  of  inversely 
as  the  square  of  the  barometric  pressures.  The  correct  height,  no  doubt, 

'Chimneys  for  Crude  Oil,  C.  R.  W.-ymouth,  Trans.  Am.  Soc.  M.  E.,  Dec.,  1912 

87 


falls  somewhere  between  the  two  values  as  larger  flues  are  usually  used  at 
the  higher  altitudes,  whereas  to  obtain  the  ratio  of  the  squares,  the  flues 
must  be  the  same  size  in  each  case,  and  again  the  effect  of  an  increased 
velocity  of  a  given  weight  of  air  through  the  fire  at  a  high  altitude,  on  the 
combustion,  must  be  neglected.  In  making  capacity  tests  with  coal  fuel, 
no  difference  has  been  noted  in  the  rates  of  combustion  for  a  given  draft 
suction  measured  by  a  water  column  at  high  and  low  altitudes,  and  this  would 
make  it  appear  that  the  correct  height  to  use  is  more  nearly  that  obtained 
by  the  inverse  ratio  of  the  barometric  readings  than  by  the  inverse  ratio 
of  the  squares  of  the  barometric  readings.  If  the  assumption  is  made  that 
the  value  falls  midway  between  the  two  formulae,  the  error  in  using  a  stack 
figured  in  the  ordinary  way  by  making  the  height  inversely  proportional 
to  the  barometric  readings,  would  differ  about  10  per  cent  in  capacity  at  an 
altitude  of  10000  ft.,  which  difference  is  well  within  the  probable  variation 
of  the  size  determined  by  different  methods.  It  would,  therefore,  appear 
that  ample  accuracy  is  obtained  in  all  cases  by  simply  making  the  height 
inversely  proportional  to  the  barometric  readings  and  increasing  the  diameter 
so  that  the  stacks  used  at  high  altitudes  have  the  same  frictional  resistance 
as  those  used  at  low  altitudes,  although,  if  desired,  the  stack  may  be  made 
somewhat  higher  at  high  altitudes  than  called  for  in  order  to  be  safe. 

The  increase  of  stack  diameter  necessary  to  maintain  the  same  friction 
loss  is  inversely  as  the  two-fifths  power  of  the  barometric  pressure. 

Table  8-3.     Stack  Capacities,  Correction  Factors  for  Altitudes 

Altitude,  height  Normal  R>  ratio  barometer  R"'  ™''O 

in  feet  above  h    :     JJv  reading  sea  R!  increase  in  stack 


1  led  aoove  L        „   ,  reauing  bea 

sea  level  barometer  ,eve,  ,0  *ltitude 


diameter 


0 

30.00 

1.000 

1.000 

1.000 

1000 

28.88 

1.039 

1.079 

1.015 

2000 

27.80 

1.079 

1.164 

1.030 

3000 

26.76 

1.121 

1.257 

1.047 

4000 

25.76 

1.165 

1.356 

1.063 

5000 

24.79 

1.210 

1.464 

1.079 

6000 

23.87 

1.257 

1.580 

1.096 

7000 

22.97 

1.306 

1.706 

1.113 

8000 

22.11 

1.357 

1.841 

1.130 

9000 

21.28 

1.410 

1.988 

1.147 

10000 

20.49 

1.464 

2.144 

1.165 

Table  8-3  gives  the  ratio  of  barometric  readings  of  various  altitudes 
to  sea  level,  values  for  the  square  of  this  ratio  and  values  of  the  two-fifths 
power  of  this  ratio.  These  figures  show  that  the  altitude  affects  the  height 
to  a  much  greater  extent  than  the  diameter,  and  that  practically  no  increase 
in  diameter  is  necessary  for  altitudes  up  to  3000  ft. 

For  high  altitudes  the  increase  in  stack  height  necessary  is,  in  some 
cases,  such  as  to  make  the  proportion  of  height  to  diameter  impracticable. 
The  method  to  be  recommended  in  overcoming,  at  least  partially,  the  great 
increase  in  height  necessary  at  high  altitudes  is  an  increase  in  the  grate  sur- 
face of  the  boilers  which  the  stack  serves,  in  this  way  reducing  the  combus- 
tion rate  necessary  to  develop  a  given  power  and  hence  the  draft  required 
for  such  combustion  rate. 

88 


CHAPTER  IX 

Boilers 

THE  boiler  equipment  is  the  production  center  of  the  heating  system 
and  the  point  where  the  bulk  of  the  operating  expense  is  centered.     For 
this  reason,  a  heating  plant  can  be  successful  and  economical  only  if 
the  boiler  equipment  is  of  correct  type,  good  material  and  workmanship, 
w  ell  proportioned  from  the  standpoint  of  its  work  and  ample  in  capacity. 

Service  from  a  heating  system  cannot  properly  be  termed  satisfactory 
unless  the  desired  heating  effect  is  secured  without  waste  of  fuel  and  without 
excess  labor  at  the  boilers,  so  it  is  the  endeavor  of  this  chapter  to  promote 
a  better  understanding  of  the  boiler  parts  and  what  they  should  do. 

Due  consideration  should  be  given  to  the  proper  selection  of  a  boiler, 
not  only  as  to  size  and  capacity,  but  also  as  to  its  adaptability  to  the  existing 
local  conditions  which,  if  not  properly  considered,  may  affect  the  success  of 
the  entire  plant. 

It  is  not  intended  in  this  discussion  to  cover  any  details  of  boiler  con- 
struction, which  properly  come  under  the  province  of,  and  can  best  be  solved 
by,  the  boiler  makers  themselves. 

Steam  boilers  have  been  built  in  one  form  or  another  for  nearly  200 
years,  yet  today  they  are  the  least  understood  of  all  the  important  elements 
which  make  up  a  power  or  heating  plant. 

If  it  were  not  necessary  to  consider  the  efficiency  of  the  performance 
of  a  steam  boiler,  such  as  the  number  of  pounds  of  water  evaporated  by  a 
pound  of  fuel,  or  the  relation  of  grate  surface  to  heating  surface,  etc.,  the 
problem  would  be  simple. 

All  the  years  of  experience  and  the  thousands  of  evaporating  tests 
made  have  not  produced  any  definite  and  reliable  rule  or  formula  for  cal- 
culating either  the  amount  of  steam  that  will  be  generated  per  hour  with  a 
given  fuel  or  the  quantity  of  steam  in  pounds  produced  per  pound  of  fuel 
burned  in  the  furnace. 

Lucke*  says:  "There  is  no  absolute  measure  of  boiler  performance  as 
to  capacity  or  efficiency  as  a  basis  of  comparison  to  measure  the  goodness 
of  a  boiler  as  a  boiler;  comparison  must,  therefore,  be  between  one  and 
another  boiler,  or  one  and  another  service  condition;  one  boiler  may  be  said 
to  be  better  than  another,  or  one  condition  more  favorable  and  another 
worse,  for  the  result  desired,  but  hardly  more  than  this  is  possible." 

For  commercial  purposes,  boiler  capacities  seem  to  be  quite  well  stand- 
ardized, boilers  used  for  heating  work  being  rated  in  capacity  of  square 
feet  of  steam  radiation,  and  boilers  for  power  work  in  boiler  horse-power. 

The  boiler  capacity  rating  in  square  feet  is  based  on  equivalent  cast- 
iron  direct  radiation  with  condensation  rate  of  ^4  Ib.  steam  per  sq.  ft.  per  hr. 

The  American  Society  of  Mechanical  Engineers  in  1885  adopted  a 
double  definition  of  the  Boiler  Horsepower  as  follows: 

(a)  The  evaporation  of  34.5  Ib.  water  per  hr.  from  and  at  212  deg.  fahr. 

*  Engineering  Thermodynamics 

89 


(b)  The  absorption  by  water,  between  fuel  conditions  and  that  of  the 
steam  leaving  the  boiler,  of  33,305  B.t.u.  per  hr. 

A  steam  boiler  consists  of  the  following  essential  parts:  A  furnace  in 
which  the  combustion  of  the  fuel  takes  place;  a  vessel  to  contain  water  to 
be  evaporated;  a  steam  space  where  the  steam  is  liberated  and  where  the 
generated  steam  is  contained ;  a  heating  surface  to  transmit  the  heat  of  the 
furnace  to  the  water;  a  smoke  pipe  to  carry  away  the  products  of  combustion, 
and  various  attachments,  such  as  gauges,  damper  regulators,  safety  valves,  etc. 

A  proper  relation  of  the  first  four  parts  to  each  other  constitutes  a  suc- 
cessful heating  boiler. 

It  is  of  prime  importance  that  the  furnace  is  of  proper  design  as  regards 
grate  area,  size  of  combustion  chamber,  ash  pit,  etc.,  to  give  most  efficient 
operation,  permitting  the  consumption  of  the  maximum  effective  quantity 
of  fuel  per  square  foot  of  grate  area.  Further  references  will  be  made  to 
importance  of  selecting  the  proper  kind  of  grates  for  the  various  grades  of 
fuel  available  in  various  localities. 

The  water  space  or  the  water-holding  capacity  of  a  boiler  does  not  al- 
ways receive  enough  attention.  It  should  be  remembered  that  the  boiler 
which  holds  the  greatest  quantity  of  water  at  or  near  the  normal  water  line 
for  given  size  or  capacity  is  the  safest  one  to  use,  because  in  such  a  boiler 
the  water  line  is  not  so  readily  brought  down  to  and  below  the  danger  point, 
as  compared  with  another  having  only  about  half  the  water-holding  capacity. 

An  investigation  of  the  various  cast-iron  boilers  to  which  our  remarks 
regarding  the  water-holding  capacity  particularly  refer,  will  show  that  there 
is  an  astonishing  difference  in  this  particular  feature.  Selecting  two  boilers 
of  the  same  capacity  but  of  different  makes,  it  will  be  found  that  the  water- 
holding  capacity  at  or  near  normal  water  line  varies  as  much  as  1  to  4. 
It  stands  to  reason  that  the  boiler  from  which  4  gal.  of  water  can  be  with- 
drawn by  lowering  the  water  line  ^  in.  will  be  safer  than  the  boiler  which 
shows  1/2  in.  lower  water  with  loss  of  only  1  gallon. 

Boiler  manufacturers  recognize  more  and  more  that  if  a  boiler  is  to  be 
successful  the  steam  space  should  be  liberal.  The  velocity  with  which  the 
steam  bubbles  are  separated  from  the  water  in  the  liberating  space  is  ex- 
tremely high.  A  boiler  with  limited  steam-liberating  surface  will  very  likely 
lose  its  water  under  heavy  load  conditions  because  under  the  influence  of 
this  velocity,  particles  are  carried  over  with  the  steam  into  the  piping  system. 

The  heating  surface  of  a  boiler  includes  all  parts  of  the  boiler  shell, 
flues,  tubes,  etc.,  covered  by  water  and  exposed  to  hot  gases.  Surface  hav- 
ing steam  on  one  side  and  hot  gases  on  the  other  is  superheating  surface. 

The  American  Society  of  Mechanical  Engineers  recommends  that  in 
measuring  heating  surface,  the  side  next  to  the  gases  be  used.  Thus  when 
estimating  the  heating  surface  of  water-tube  boilers,  the  outside  areas  of  the 
tubes  are  measured,  and  for  return-tubular  or  fire-box  boilers  the  inside 
areas  are  measured. 

The  heat  generated  by  the  combustion  of  fuel  permeates  from  the  fur- 
nace through  the  heating  surface  to  the  water  in  the  boiler.  As  the  process 
of  combustion  proceeds,  the  heat  liberated  is  immediately  absorbed,  partly 
by  heat  from  the  freshly  added  fuel,  but  mainly  from  the  gaseous  products  of 

90 


combustion.  The  absorption  of  heat  by  these  substances  causes  a  rise  in 
their  temperature  and  from  these  gases  the  heat  is  transmitted  through  the 
heating  surfaces  into  the  boiler-  water.  This  transmission  of  heat  takes 
place  in  three  distinct  ways,  each  of  which  is  governed  by  a  definite  law  not 
applicable  to  the  others. 

Before  the  heat  reaches  the  body  of  the  boiler  water,  it  changes  its  mode 
of  travel  at  least  twice.  It  is  first  imparted  to  the  heating  surface:  (a)  by 
radiation  from  the  hot  fuel  bed,  the  furnace  walls  and  the  luminous  flames, 
and  (b)  by  convection  from  the  hot  moving  gaseous  products  of  combustion. 
Upon  reaching  the  heating  surfaces  the  heat  changes  its  mode  of  trans- 
mission and  passes  through  the  soot,  metal  and  scale  to  the  inner  surface, 
which  is  in  contact  with  the  water,  purely  by  conduction.  From  the  wet 
side  of  the  heating  surface  the  heat  is  carried  into  the  boiler  water  mainly 
by  convection.* 

The  water  in  the  boiler  can  absorb  only  that  heat  called  the  "heat 
available  for  the  boiler,"  which  is  above  its  own  temperature.  Heat  below 
this  temperature  will  not  flow  into  the  boiler  and  is,  therefore,  not  available. 

A  commercial  boiler  absorbs  only  part  of  the  available  heat,  which 
expressed  as  a  percentage,  is  the  true  boiler  effciency.  This  efficiency  de- 
pends chiefly  on  the  arrangement  of  the  heating  surfaces.  Therefore,  from 
point  of  economy  in  operation,  the  heating  surface  available  and  its  arrange- 
ment should  be  carefully  considered  by  the  designer  when  selecting  boiler 
equipment  for  a  heating  plant. 

The  boiler  efficiency,  which  is  the  only  true  measure  of  the  ability  of 
the  boiler  to  absorb  heat,  is  expressed  by  the  following  equation: 

„-,  .,         ,  .  heat  absorbed  bv  boiler 

I  rue  boiler  ef  Iiciencv  =  7  .,  . , — TT*   .    ., 

heat  available  tor  boiler 

The  efficiencies  ordinarily  used  in  commercial  boiler  tests  may  not  rep- 
resent the  true  performance  of  the  boiler  under  actual  working  conditions. 

Boiler  capacities  as  given  in  catalogues  of  manufacturers  of  heating 
boilers  are  based  on  the  efficiencies  obtained  in  the  testing  laboratories,  and 
these  may  not  be  representative  of  true  conditions.  In  selecting  a  boiler 
for  a  heating  plant,  due  allowance  should  be  made  to  take  care  of  this  dis- 
crepancy by  adding  a  factor  of  safety  to  compensate  for  the  difference  in 
laboratory  and  actual  working  conditions.  This  allowance,  which  may 
be  called  the  safety  factor  to  be  added  to  the  theoretical  capacity,  varies 
widely  for  the  various  types  of  boilers.  Before  determining  the  safety  factor 
to  be  added  to  the  commercial  rating,  the  designer  should  carefully  consider 
the  type  of  boiler,  the  kind  of  fuel  to  be  used,  and  the  kind  of  attention  the 
plant  will  receive,  as  all  these  bear  on  the  performance  and  efficiency. 

The  necessity  of  providing  an  extra  safety  factor  is  recognized  also  by 
the  heating  trade  and  various  trade  associations  that  have  established  rules 
and  regulations  for  guidance  of  members  in  determining  boiler  capacities. 

The  difficulty  in  obtaining  the  more  desirable  grades  of  coal  has  re- 
sulted in  an  increasing  tendency  to  use  coals  which  are  more  readily  obtain- 
able and  lower  in  cost.  The  grates  of  the  boilers  should  therefore  be 

*  Bulletin  IS,  United  States  Bureau  of  iMines 

91 


properly  designed  for  the  fuel  which  will  most  likely  be  used.  Different 
authorities  have  a  wide  range  of  opinion  as  to  the  width  of  the  air  space 
that  should  be  used  between  grate  bar  openings  for  a  given  grade  of  fuel. 

Professor  Gebhardt  recommends  an  air  space  of  %  in.  between  the  grate 
bars  and  bars  %  in.  wide  for  power  boilers  and  for  average  bituminous  coal. 

For  No.  3  buckwheat  coal  an  air  space  of  3/16  in.  and  for  No.  1  buck- 
wheat 5/16  in.  is  recommended. 

Grate  areas  are  usually  determined  in  proportion  to  the  heating  surface 
of  the  boiler,  that  is,  for  a  given  fuel,  the  grate  surface  and  heating  surface 
have  a  fixed  ratio.  For  normal  operation,  a  ratio  of  grate  surface  to  heat- 
ing surface  of  1  to  35  to  45  develops  the  rated  capacity  of  the  boiler,  while 
for  fine  coal  or  overload  conditions,  a  ratio  of  1  to  25  is  desirable. 

For  return-tubular  boilers  and  water-tube  boilers,  the  following  table 
shows  the  usual  ratios  of  grate  surface  to  heating  surface  and  also  the  grate 
bar  openings  applying  with  these  ratios  when  using  soft  coal  fuel. 

Table  9-1.     Grate  Surfaces  for  Soft  Coals 


Coal 

Grate  bar  openings 
Mine  run            Slack 

Ratio  of  grate 
heating  s 
Mine  run 

surface  to 
Slack 

Va.,  W.  Va.,  Md.,  Pa       

y-in 

^-in. 

J4 

1:55 
1:50 
1:45 
1:45 

1:50 
1:45 
1:40 
1:40 

Ohio,  Ky.,  Tenn.,  Ala    

3/  _  I/ 

111.,  Ind.,  Kan.,  Okla        

3/  _  ]  y 

Col.  and  Wyo 

3/ 

_ 

Determination  of  the  amount  of  grate  surface  to  be  used  under  given 
conditions  involves  the  available  draft  as  well  as  the  fuel  to  be  used.  The 
curves  given  in  Figure  8-9,  page  85,  show  how  much  draft  is  necessary  for 
burning  different  coals  at  various  rates  of  combustion. 

The  draft  required  to  overcome  resistances  in  the  boiler  is  also  given  in 
Chapter  8,  pages  83  and  84.  These  losses  in  the  boiler  and  furnace  must  be 
deducted  from  the  total  available  draft  to  determine  the  draft  available  for 
the  fuel  bed. 

The  capacity  of  the  boiler  and  the  B.t.u.  to  be  developed  being  known, 
the  number  of  pounds  of  coal  to  be  burned  can  be  readily  computed.  The 
total  grate  area  required  is  found  by  dividing  the  total  number  of  pounds  of 
coal  to  be  burned  by  the  rate  of  combustion  taken  from  Figure  8-9,  page  85. 

Hand-fired  return  tubular  and  water-tube  boilers  are  readily  operated 
at  the  rates  of  combustion  in  pounds  of  coal  per  square  foot  of  grate  area 
given  in  Table  9-2. 

Small  boilers  of  the  residence-heating  type  usually  burn  coal  at  rates 
ranging  from  1  to  5  Ib.  per  sq.  ft.  of  grate  surface  per  hr.  and  in  larger  heating 

Table  9-2.    Rates  of  Combustion  for  Various  Coals 

Anthracite 15  Ib.  per  sq.  ft.  per  hr. 

Semi-anthracite 16  " 

Semi-bituminous 18 

Eastern  bituminous 20  " 

Western  bituminous 28  " 

9-2 


boilers  the  ratio  ranges  from  4  to  12  Ib.  per  sq.  ft.  of  grate  surface  per  hr. 

These  low  rates  of  combustion  are  the  result  of  demands  for  less  fre- 
quent attention,  in  order  that  the  man  who  fires  the  boiler  may  devote  time 
to  other  work.  In  consequence,  heating  boilers  are  expected  to  do  their 
work  when  fired  once  every  hour  or  two  or  in  residence  heating,  once  in  six 
to  eight  hours,  whereas  power  boilers  are  fired  at  regular  intervals  of  five 
to  ten  minutes.* 

Another  reason  why  heating  boilers  require  different  firing  methods 
to  burn  bituminous  coals  successfully  is  that  the  space  in  the  fire-box  above 
the  fuel  bed  is  usually  very  much  smaller  than  is  the  corresponding  space  in 
power  boilers.*  This  space,  known  as  the  combustion  chamber,  is  where  the 
smoky  gases  driven  off  from  the  coal  must  become  mixed  with  air  and  burn. 
The  more  rapidly  the  combustible  gases  are  driven  off  from  the  coal,  the 
larger  must  be  the  space  necessary  for  burning  them  completely.  The 
relatively  small  combustion  space  in  heating  boilers  makes  it  important 
that  the  firing  be  done  in  a  way  to  prevent  the  gases  from  being  driven  off 
too  rapidly. f 

The  type  of  boiler  to  fit  the  given  conditions  most  satisfactorily  depends 
upon  the  physical  conditions  of  the  plant,  as  well  as  the  type  of  heating 
system  selected.  The  success  of  one  depends  upon  the  other.  For  this 
reason  boiler  selection  is  discussed  also  in  Chapter  10,  Selection  of  the 
Proper  Type  of  Steam  Heating  System. 

On  account  of  the  great  variation  of  governing  conditions,  no  attempt 
will  be  made  here  to  discuss  in  detail  the  method  of  installation  of  the  boilers 
or  their  connections. 

Precautions  should  be  taken  in  the  design  of  the  boiler  plant  to  mini- 
mize bad  effects  from  priming. 

Liberal  bleeder  or  drip  connections  from  the  boiler  header,  connecting 
directly  to  the  return  header,  eliminate  a  great  percentage  of  this  trouble. 

Priming  in  most  cases  is  due  to  the  presence  of  grease  or  oil  in  the  boiler 
or  to  the  presence  in  the  water  of  certain  alkalies  which  cause  the  water  to 
foam  or  bubble,  and  be  carried  into  the  piping  system  by  the  steam.  Before 
it  can  be  expected  to  perform  its  functions  uniformly,  effectively  and  economi- 
cally, a  boiler  must  be  thoroughly  cleansed  of  oil,  scale,  dirt  and  other  im- 
purities. The  priming  of  boilers  is  not  confined  to  any  particular  type  or 
make.  The  plant  designer  will  safeguard  the  interest  of  the  owner  and  him- 
self as  well,  if  he  makes  sure  that  bleeder  connections  are  made  to  protect 
the  boiler  in  case  of  priming  and  that  his  instructions  about  proper  cleaning 
of  the  boiler  and  the  entire  heating  system  are  carried  out  in  full  by  the 
heating  contractor. 

For  thoroughly  cleaning  a  boiler,  the  safety  valve  should  be  removed 
and  a  sufficient  quantity  of  soda  ash  should  be  placed  within  the  boiler  to 
cause  saponification  of  oils  and  grease.  A  temporary  overflow  pipe  should 
be  run  to  waste  from  the  safety  valve  outlet  or  highest  point  of  the  boiler. 

*  Technical  Paper  180,  United  States  Bureau  of  Mines 

t  For  further  reference  to  the  importance  and  effect  of  combustion  space  see  Technical  Papers  63,  80 
and  137  of  the  United  States  Bureau  of  Mines 

93 


With  a  moderate  fire  and  the  addition  of  feed  water  as  required  to 
prevent  injury,  the  foaming  of  the  boiler  will  cause  the  flow  of  oil  and  grease 
through  the  overflow  pipe  to  waste.  After  thorough  boiling,  the  fire  should 
be  drawn  and  when  cool,  the  water  should  be  withdrawn  and  then  the 
boiler  should  be  thoroughly  washed  with  clean  water  to  remove  dirt  and 
chemicals.  This  treatment  for  boilers  should  be  repeated  whenever  neces- 
sary as  indicated  by  abnormal  fluctuations  of  the  water  line  or  by  the  appear- 
ance of  foaming. 

Damper  control  is  an  important  feature  of  boiler  operation.  There  are 
two  classes  of  damper  regulators,  (1)  those  that  move  the  damper  for  slight 
changes  in  the  steam  pressure,  with  a  proportional  movement  due  to  the 
change  in  pressure  and  (2)  those  that  operate  the  dampers  between  extreme 
positions  when  the  steam  pressure  changes.  The  first  is  preferable  from  the 
standpoint  of  economical  combustion. 

As  mentioned  in  Chapter  8,  the  fuel  in  a  steam-boiler  furnace  is  made  to 
burn  by  passing  through  it  a  current  of  air,  which  supplies  the  necessary 
oxygen  and  carries  away  the  products  of  combustion.  A  liberal  supply  of 
available  air  is  therefore  very  important.  Yet  in  many  cases  the  space 
allotted  to  the  boiler  room  is  inside,  small  and  without  adequate  air  supply 
for  combustion.  Boiler  rooms  should  be  of  ample  size  and  depth  to  ac- 
commodate the  boilers  without  crowding,  and  should  have  an  abundant 
supply  of  air  for  both  combustion  and  ventilation.  The  space  in  front  of 
the  boilers  should  be  ample  for  convenience  and  comfort.  A  cramped  boiler 
room  is  not  only  unsightly,  but  it  also  adds  to  the  difficulty  of  taking  care  of 
the  plant  efficiently.  The  attendant,  when  firing,  has  to  stand  about  4^  or 
5  ft.  from  the  front  of  the  furnace  and  usually  about  12  to  18  in.  to  the 
left  of  a  straight  line  running  through  the  centre  of  the  furnace  door.  He 
should  have  ample  room  to  swing  his  scoop  from  the  coal  pile  into  any  part 
of  the  furnace. 

Many  a  fireman  is  blamed  for  the  poor  economy  shown  by  the  plant  he 
operates  where  the  dissatisfaction  should  be  charged  at  least  partially  to 
the  plant  designer.  It  is  difficult  to  keep  skillful  firemen  in  a  small,  poorly- 
kept  boiler  room. 

The  size  and  type  of  boiler  to  be  specified  and  the  evaporation  the  boiler 
will  give  are  problems  in  which  the  advice  of  the  boiler  maker  may  well  be 
considered.  The  boiler  maker  is  usually  quite  willing  to  co-operate  if 
provided  with  such  data  as  the  total  radiation  in  square  feet  and  pounds  of 
condensation,  total  condensation  of  the  steam  and  return  lines  in  equivalent 
square  feet  of  radiation  and  pounds,  the  quality  and  size  of  fuel  available, 
the  size  and  height  of  chimney  and  the  firing  period  to  be  allowed. 


CHAPTER  X 

Selection  of  the  Proper  Type  of  Steam 
Heating  System 

THE  heat  requirements  of  the  building  having  been  determined,  the 
next  step  is  the  selection  of  the  proper  type  of  steam  heating  system 

to  fit  the  particular  needs.  It  is  essential  that  the  system  of  supply 
and  return  piping  shall  be  such  that  the  circulation  of  steam  will  be  posi- 
tively and  uniformly  maintained  and  that  the  air  and  the  products  of 
condensation  shall  be  disposed  of  continuously  in  order  that  the  system  shall 
be  efficient  as  well  as  economical  in  operation. 

Two  broad  types  of  two-pipe  steam  heating  systems  have  proved  so 
successful  during  the  past  20  years  that  their  use  has  become  the  modern 
standard  practice. 

Each  type  is  flexible  in  its  application  and  may  be  modified  in  detail 
to  meet  the  variable  conditions  that  arise. 

These  two  types  are  the  Open  Return-Line  or  Modulation  System  and 
the  Vacuum  System. 

In  the  Open  Return-Line  or  Modulation  System  a  pressure  slightly  above 
atmosphere  is  maintained  in  the  supply  piping  and  radiators,  the  products 
of  condensation  flowing  by  gravity  to  a  point  of  disposal  at  which  atmos- 
pheric or  occasionally  slightly  lower  pressure  exists.  Here  the  air  is  vented 
through  suitable  devices  and  the  condensation  is  either  returned  to  the  boiler, 
if  one  is  provided,  or  wasted  to  the  sewer,  if  the  source  of  supply  is  a  so-called 
"street  system." 

In  its  simplest  form  a  modulation  system  consists  of  a  low-pressure 
steam  boiler  and  its  appurtenances,  supply  piping,  radiating  surfaces,  a 
modulation  or  graduated  control  valve  at  the  inlet  of  each  radiator  and 
a  thermostatic  return  trap  at  the  outlet,  a  system  of  return  piping  with  a 
device  at  the  end  to  automatically  remove  the  air  and  return  the  water  of 
condensation  to  the  boiler.  Under  favorable  conditions  the  boiler  operates, 
after  initial  heating,  for  long  periods  under  vapor  or  partial  vacuum,  but 
due  to  the  flexibility  of  the  system,  higher  pressures  are  permitted  in  severe 
weather,  when  maximum  heating  requirements  exist.  It  is  very  important 
that  the  steam  pressure  shall  be  closely  controlled  by  means  of  an  extremely 
sensitive  damper  regulator  which  will  maintain  the  pressure  always  within 
a  few  ounces  of  that  for  which  the  regulator  is  set,  thus  making  it  possible 
to  operate  the  boiler  at  or  near  atmospheric  pressure  during  mild  weather. 
The  damper  regulator  also  serves  to  quickly  check  the  fire  whenever  there 
is  a  tendency  for  the  pressure  to  rise,  due  either  to  a  sudden  closing  off  of  a 
considerable  amount  of  the  radiating  surface  or  carelessness  on  the  part  of 
the  attendant,  after  firing  up  the  boiler. 

For  reasons  of  safety  it  is  necessary  that  the  device  returning  the  con- 
densation to  the  boiler  shall  function  properly  when  the  steam  pressure 

95 


rises  above  the  normal  operating  point  and  even  when,  for  short  period, 
it  reaches  the  blowing-off  pressure  of  the  safety  valve,  which  is  ordinarily 
not  over  10  Ib.  in  an  open  return-line  system. 

In  the  Vacuum  System,  a  pressure  at  or  slightly  above  or  below  at- 
mospheric is  maintained  in  the  supply  piping  and  radiators,  and  air  and  the 
water  resulting  from  condensation  of  steam  are  continuously  removed  by 
mechanical  apparatus  which  maintains,  in  the  return  piping,  a  pressure  less 
than  atmospheric.  The  partial  vacuum  required  to  remove  the  air  and 
condensation  is  produced  and  maintained  by  mechanical  displacement 
of  the  vapors  of  condensation. 

The  two  types  of  systems  are  similar,  in  that  a  positive  circulation  of 
steam  is  secured  by  the  natural  flow  of  the  heating  medium  from  a  higher 
to  a  lower  pressure.  The  distinguishing  difference  between  the  two  types 
lies  in  the  method  of  removing  and  disposing  of  the  air  and  the  products  of 
condensation. 

In  either  modulation  or  vacuum  systems,  modulation  or  graduated 
supply  valves,  when  attached  to  the  radiators  permit  control  of  the  room 
temperature  by  simple  hand  operation,  ensuring  a  distinct  saving  in  fuel. 
The  efficiency  of  either  system  is  dependent  to  a  large  extent  upon  the  ability 
of  the  return  trap  on  the  radiator  to  free  it  of  all  air  and  water  of  condensation 
without  at  the  same  time  permitting  the  escape  of  any  steam. 

The  open-return  or  modulation  system  finds  its  widest  application  in  a 
building  covering  a  moderate  area,  in  which  the  steam  requirements  are  for 
heating  only  and  where  the  radiation  can  be  placed  high  enough  above  the 
water  line  so  that  the  condensation  will  flow  by  gravity  to  the  boiler.  The 
system  is  noiseless  in  operation,  simple  in  design,  requiring  no  power-driven 
apparatus  and  except  for  periodical  firing  of  coal  and  removal  of  ashes,  the 
attention  required  is  negligible. 

There  are  a  number  of  modifications  of  the  modulation  system,  de- 
pending upon  varying  conditions,  and  a  system  installed  in  a  residence  for 
instance,  may  be  quite  different  from  that  in  a  hotel  or  school. 

The  special  advantages  of  the  vacuum  system  can  be  realized  to  the 
fullest  extent  in  projects  such  as  the  following: 

(a)  A  group  of  buildings  scattered  over  a  considerable  area  where 
savings  in  cost  of  installation  can  be  effected  by  the  use  of  smaller  size 
supply  and  return  piping. 

(b)  One  or  more  buildings  so  located  with  respect  to  the  boiler  plant 
that  lifts  are  necessary  in  the  return  piping. 

(c)  A  plant  utilizing  the  exhaust  steam  from  the  engines  for  heating 
purposes,  wherein  the  elimination  of  the  back  pressure  will  save  directly 
in  fuel  cost  or  permit  the  engine  to  do  more  work  with  the  same  expenditure 
of  fuel. 

The  foregoing  examples  do  not  by  any  means  cover  the  entire  field  for 
use,  for  the  vacuum  system  can  be  used  in  numerous  other  types  of  build- 
ings either  as  a  regular  vacuum  system  or  in  combination  with  the  open 
return-line  system.  Indeed  the  adaptability  of  the  two  systems  to  widely 
different  operating  conditions  makes  possible  the  choice  of  one  or  the  other 
for  every  type  of  building.  In  the  following  pages  certain  general  rules 

96 


will  IK-  given  which  may  influence  the  selection  of  a  heating  system  for  any 
particular  case.  Mention  will  also  be  made  of  modifications  which  may  be 
desirable  or  necessary  to  suit  individual  conditions. 

In  determining  which  of  these  types  to  employ,  experience  is  the  best 
guide,  as  the  building  conditions  present  so  many  variable  factors  that  it 
is  impossible  to  cover  the  subject  exhaustively  within  the  space  of  this 
chapter. 

When  selecting  a  heating  system,  consideration  should  be  given  to 
the  following  points: 

(a)  Si/,e  and  type  of  building. 

(b)  Use  of  building. 

(c)  Location  of  building  and  topography  of  site. 

(d)  Construction  and  architectural  features  of  the  building. 

(e)  Source  of  steam  supply. 

(f)  Operation  and  attendance. 

SIZE  AND  TYPE  OF  BUILDING:  The  first  point  to  consider  is  the  size 
of  the  building  and  its  type. 

Residences:  The  prospective  owner  of  a  residence  is  particularly 
interested  in  the  amount  of  attention  necessary  for  operation  and  the 
economy  of  fuel.  Whether  he  attends  to  the  heating  system  himself  or 
employs  a  caretaker,  he  desires  a  plant  requiring  minimum  attendance. 

The  modulation  system  is  the  most  suitable  in  every  respect  either 
for  a  30-room  house  or  for  a  small  bungalow.  Except  for  periodical 
feeding  of  coal  and  removal  of  ashes,  the  attention  required  by  such  a 
system  is  negligible.  The  ability  to  vary  the  boiler  pressure  through  a  range 
from  the  maximum  permissible  in  very  cold  weather  to  a  pressure  at  or 
slightly  below  atmosphere  in  mild  weather,  and  to  control  the  quantity 
of  heat  given  off  from  each  radiator  by  manipulating  the  graduated  supply 
valve,  result  in  a  distinct  economy.  The  heat  emission  and  the  coal  consump- 
tion are  regulated  to  correspond  with  the  outside  temperature  and  weather 
conditions. 

Apartment  Buildings:  Apartment  buildings  are  erected  by  the  owner 
for  the  revenue  which  they  will  bring  and  a  heating  plant  which  can  be 
operated  with  greatest  fuel  saving  and  the  least  janitor  service  is  the  best 
paying  proposition.  Unless  the  building  spreads  over  too  much  ground  or 
the  overhead  return  piping  cannot  be  properly  graded  without  too  much 
complication,  the  modulation  system  is  particularly  adaptable.  The  small 
amount  of  attention  required  by  this  system  gives  the  janitor  of  the  building 
more  time  for  other  duties.  Control  of  the  amount  of  steam  admitted  into 
each  radiator  gives  the  occupant  of  each  room  or  apartment  a  convenient 
means  of  temperature  regulation. 

Store  and  Office  Buildings:  Where  no  mechanical  system  of  heating 
and  ventilation  need  be  provided  and  where  an  open-return-line  system  can 
be  applied,  the  same  type  of  heating  system  can  be  used  in  the  small  store 
building  as  described  for  residences  and  apartments.  This  also  applies 
with  equal  force  to  small  and  medium-sized  buildings  for  offices  and  other 
commercial  purposes. 

07 


Fig.  10-1.     The  entry  of  a  modern  apartment  building  showing  heat  outlets  in  the  side  walls 

Public  Buildings:  In  this  classification  may  be  included  court  houses, 
post  offices,  libraries,  and  schools  of  small  type  where  the  ventilating  systems 
are  of  the  indirect  or  direct -indirect  gravity  ventilation  type.  Such  buildings 
have,  as  a  rule,  no  other  mechanical  equipment  besides  the  heating  and 
ventilating  plant.  For  these  structures  a  modulation  system  with  open- 
line  return  is  recommended. 

98 


We  have  considered  so  far  the  type  of  building  wherein  the  area  is 
moderate,  the  steam  requirement  is  for  heating  purposes  only,  the  basement 
radiation  is  well  above  the  water  line  of  the  boiler  and  the  overhead  return 
piping  can  be  properly  graded,  as  required  in  the  open-line  system.  In 
such  cases  the  simplest  form  of  system  can  be  installed,  requiring  a  minimum 
amount  of  attention. 

Frequently,  however,  conditions  arise  wherein  the  open-return  piping 
cannot  be  run  at  a  higher  level  than  that  of  the  water  line  of  the  boiler  and 
discharge  by  gravity  into  the  boiler,  or  where  the  radiation  in  the  basement 
must  be  placed  at  or  even  below  the  boiler  water  line.  The  first  mentioned 
situation  occurs  if  the  building  covers  considerable  area  or  structural  con- 
ditions cause  t  lie  return  piping  to  be  kept  well  down  from  the  ceiling.  Where 
mechanical  ventilation  is  installed  having  indirect  radiation  placed  in  the 
basement  for  warming  the  air,  or  where  the  character  of  the  basement  rooms 
is  such  that  they  will  not  be  properly  heated  if  the  direct  radiators  are  placed 
near  the  ceiling,  it  becomes  necessary  to  locate  them  too  low  for  successfully 
returning  the  water  to  the  boilers  by  gravity.  In  such  cases  a  vented 
receiver  is  installed  and  connected  to  either  a  motor-driven  or  steam-driven 
pump.  The  receiver  contains  a  float  at  its  water  level,  the  rise  and  fall 
of  which  controls  the  operation  of  the  electric  motor  or  steam  pump,  and 
the  water  of  condensation  is  automatically  delivered  to  the  boiler.  The 
apparatus  is  placed  at  or  below  the  floor  on  a  suitable  foundation  and  the 
water  line  of  the  heating  system  is  thus  governed  by  the  level  in  the  receiver, 
regardless  of  the  water  line  of  the  boiler.  Where  no  high-pressure  steam  is 
required  for  industrial  or  other  purposes,  the  automatic  return  pump  can 
be  used  in  conjunction  with  low-pressure  boilers,  in  which  event  the  pump 
will  have  a  motor  drive. 

Where  high-pressure  steam  is  required  for  various  purposes,  one  or 
more  high-pressure  boilers  are  installed.  Steam  for  heating  is  reduced  to 
suitable  pressure  by  means  of  a  pressure-reducing  valve  and  is  circulated 
through  the  modulation  heating  system  by  gravity,  returning  to  the  vented 
receiver.  In  such  cases,  a  steam-driven  return  pump  is  installed,  taking 
steam  at  boiler  pressure  and  discharging  the  exhaust  into  the  heating 
system  through  a  suitable  oil  separator.  The  condensation  from  the  various 
pieces  of  apparatus  utilizing  high-pressure  steam  is  also  delivered  to  the 
vented  receiver  and  thence  returned  to  the  boiler. 

For  buildings  occupying  considerable  area  and  for  groups  of  buildings 
to  be  heated  from  a  common  boiler  plant,  the  vacuum  system  is  to  be 
preferred  to  the  modulation  system  with  vented  receiver  and  return  pump. 
Where  lifts  are  necessary  in  the  returns,  the  vacuum  system  is  the  best 
solution.  In  high  buildings  a  vacuum  system  is  usually  selected,  owing  to 
the  saving  which  can  be  effected  by  the  reduced  sizes  of  supply  and  return 
piping  as  well  as  radiator  inlet  valves  and  return  traps.  If  high  or  medium- 
pressure  steam  is  not  required  for  any  equipment  or  process,  low-pressure 
boilers  may  be  installed  in  connection  with  an  electrically  driven  vacuum 
l)um])  which  will  also  return  the  condensation  from  the  heating  system  to  the 
boilers.  From  an  operating  standpoint  a  vacuum  system  with  an  electri- 
c-ally driven  vacuum  pump  of  the  rotary  type  is  quite  as  simple  as  the  open- 

99 


return-line   system   or  a  modulation  system,  with  a  condensation  pump. 
Where  the  steam  requirements  for  the  building  are  such  that  high- 
pressure  boilers  are  required,  either  motor-driven  or  steam-driven  pumps 
may  be  used  depending  upon  conditions  which  will  be  touched  upon  later. 

USE  OF  BUILDING:  The  use  of  the  building,  or  the  portion  of  time 
during  which  the  building  is  in  use  and  must  be  heated,  is  an  exceedingly 
important  factor  in  the  selection  of  a  system. 

Stores,  office  buildings,  restaurants  and  the  like  are  heated  throughout 
during  the  daytime,  while  at  night  the  requirement  is  only  that  of  preventing 
the  freezing  of  plumbing,  water  pipes,  etc. 

In  school  buildings  the  ventilating  system  is  usually  put  into  operation 
about  8  o'clock  in  the  morning  and  shut  down  at  4  o'clock  in  the  afternoon. 
Rural  schools  often  do  not  have  electricity  available  for  driving  the  ventil- 
ating fans  and  in  such  cases  a  steam  engine  is  installed  for  the  purpose.  The 
boilers  are  usually  operated  at  about  30-lb.  pressure,  steam  for  heating  pur- 
poses is  reduced  to  1-lb.  pressure  and  the  condensation  is  delivered  to  the  boil- 
ers by  an  automatic  return-pump  and  receiver.  The  exhaust  steam  from  the 
engine  and  pump  are  utilized  in  the  heating  system  after  extraction  of  the 
oil  by  passing  the  steam  through  an  oil  separator. 

Where  electric  current  is  available  a  combination  modulation  and 
vacuum  system  may  be  installed.  In  this  case  the  boilers  are  operated  at 
low  pressure.  While  the  mechanical  ventilating  system  is  in  use,  a  motor- 
driven  vacuum  pump  is  employed  to  remove  the  air  and  the  water  of  con- 
densation from  the  heating  system  and  discharge  the  water  into  the  boilers. 
As  soon  as  the  ventilating  system  is  shut  down,  the  vacuum  pump  may  be 
stopped  and  the  direct  heating  system  is  then  operated  as  an  open-return 
line  system,  discharging  the  returns  through  a  suitable  trap,  by  gravity  to 
the  boiler.  At  night  the  heating  plant  requires  almost  no  attention. 

The  heating  of  a  theatre  may  be  accomplished  in  very  much  the  same 
manner.  In  this  instance  however,  the  ventilating  system  is  in  use  in  the 
afternoons  and  evenings,  during  which  the  plant  is  operated  as  a  vacuum 
system.  After  the  close  of  the  night  performance  the  change  is  made  to  a 
modulation  system. 

Heating  systems  in  churches  are  usually  operated  intermittently.  Where 
no  mechanical  ventilation  is  to  be  provided  and  where  all  radiation  can 
be  placed  high  enough  above  the  water  line  for  gravity  return  of  the  water 
of  condensation  to  the  boiler,  a  modulation  system  will  give  excellent  results. 
It  has  the  special  advantage  that  by  eliminating  the  use  of  wet  returns,  the 
danger  of  freezing  of  pipes,  due  to  intermittent  operation,  can  be  avoided. 
Heating  systems  in  churches  as  a  rule  do  not  receive  the  best  of  attention 
and  therefore  the  simpler  the  installation,  the  more  satisfactory  the  service. 
The  operation  of  the  modulation  system  in  draining  the  condensation  back  to 
the  boiler  entirely  by  gravity  also  avoids  the  slight  noise  that  usually  accom- 
panies the  action  of  mechanical  devices,  if  the  latter  are  employed  for  handling 
condensation.  Where  mechanical  ventilation  is  installed  in  a  church  the 
combination  of  a  modulation  and  vacuum  system  will  be  found  to  operate 
with  the  same  reliability  as  described  in  connection  with  school  buildings. 

100 


The  use  of  the  motor-driven  vacuum  pump  will  ensure  a  rapid  as  well  as 
noiseless  circulation  of  steam  and  quick  removal  of  the  air  during  the  warm- 
ing-up period.  If  it  is  not  possible  to  eliminate  the  wet  returns  where  the 
combination  system  is  installed,  care  must  be  used  to  properly  protect 
the  pipes  against  freezing. 

Hotels,  hospitals,  institutions,  asylums  and  the  like  have  a  24-hour 
period  during  the  entire  heating  season.  It  is  absolutely  essential  that  the 
service  shall  be  continuous.  Not  only  must  the  system  be  economical  and 
noiseless  in  its  operation,  but  it  must  also  be  very  flexible  to  meet  the  varying 
demands  of  outside  temperatures  and  weather.  The  comfort  of  each  indi- 
vidual must  be  considered,  and  as  is  well  known,  the  preferences  vary.  In 
all  the  above  cases  there  are  demands  for  high  and  reduced-pressure  steam 
for  various  purposes  and  it  is  therefore  probable  that  high-pressure  boilers 
will  be  installed. 

\Yith  a  single  building  covering  a  moderate  area,  an  open-return-line 
system  in  conjunction  with  an  automatic  pump  and  return  tank,  together 
with  modulation  supply  valves  on  the  radiators,  will  meet  all  of  the  re- 
quirements outlined  above.  For  a  group  of  buildings  or  a  single  building 
covering  considerable  area,  a  vacuum  system  will  be  more  flexible. 

In  addition  to  all  of  the  benefits  of  the  modulation  system,  the  vacuum 
pump  will  circulate  steam  very  rapidly  through  the  system,  which  is  an 
important  factor  when  quick  heating  up  becomes  necessary.  A  further 
advantage  is  the  saving  effected  through  the  ability,  in  mild  weather,  when 
t  he  demand  for  steam  is  light,  to  distribute  a  small  volume  of  steam  through- 
out the  entire  system  as  needed.  With  the  modulation  supply  valve  on 
c;ieh  radiator  properly  adjusted,  or  with  the  radiators  controlled  auto- 
matically by  thermostats,  rooms  on  the  cold  side  of  the  building  will  receive 
t  he  proper  amount  of  heat  and  those  on  the  warm  side  will  not  be  overheated 
and  all  this  is  brought  about  with  a  relatively  small  amount  of  steam. 

LOCATION  OF  BUILDING  AND  TOPOGRAPHY  OF  SITE:  Location  of  the 
building  and  the  general  topography  of  the  site  not  only  affect  the  type  of 
heating  system  used  but  may  also  influence  the  kind  of  boiler  selected. 

For  example,  in  rural  districts  electricity  may  not  be  available  as  a 
motive  power  or  it  may  not  be  advisable  on  account  of  its  unreliability. 
Where  mechanical  ventilation  is  required,  as  for  example  in  a  school  or 
other  similar  building,  a  steam  engine  will  be  required  for  driving  the  fan. 
A  type  of  boiler  capable  of  generating  steam  at,  say  25  to  30-lb.  pressure 
must  be  selected.  The  steam  for  heating  is  reduced  to  1-lb.  pressure.  A 
low-pressure  steam  pump  will  have  to  be  installed  to  return  the  condensation 
to  the  boilers,  operating  in  conjunction  with  a  vented  receiver  and  an  auto- 
matic float  control  device.  The  receiver  must  be  located  a  sufficient  distance 
below  the  bottom  of  the  indirect  radiators  so  as  to  obtain  the  necessary 
fall  required  to  secure  a  rapid  flow  of  water  by  gravity.  A  modulation 
system  of  heating  with  open  return  line  to  receiver  will  give  excellent  results 
and  if  the  direct  radiators  are  provided  with  graduated  supply  valxcs. 
the  quantity  of  heat  given  off  by  each  may  be  easily  controlled  by  hand. 

101 


Fiji.  10-2.     Arrangement  of  cast-iron  wall  radiation  in  cove  of  ceiling  in  a  grill  room.     This  can 

also  be  employed  in  barber  shops  and  other  basement  rooms  where  a  modulation  system 

is  installed  and  it  is  necessary  to  keep  the  radiators  well  above  the  boiler  water  line. 

Operation  of  the  steam  inlet  valves  of  such  radiators  can,  if  necessary,  be 

facilitated  by  the  use  of  extension  stems  or  chain  attachments 


F'ig.  10-:i.     Cast-iron  wall  radiation  in  garage.     The  radiation  is  placed  at  some  distance  from  the  floor 
level  to  avoid  being  damaged  by  cars  and  to  prevent  injury  to  tires  from  heat 

102 


The  topography  of  the  site  may  make  the  return  of  condensation 
difficult  or  impractical  except  by  the  use  of  vacuum  or  by  direct  pumping. 

Where  lifts  are  necessary  in  the  return  the  vacuum  system  is  the  only 
solution. 

A  group  of  buildings  spread  out  over  considerable  area,  supplied  with 
steam  from  a  central  boiler  plant,  may  require  the  use  of  the  vacuum  system 
in  order  to  balance  the  pressure  differential  between  the  supply  and  return 
at  the  several  buildings,  particularly  if  it  is  contemplated  to  add  new  build- 
ings to  the  group  at  sonic  future  time.  A  further  distinct  advantage  of  a 
vacuum  system  under  these  conditions  lies  in  the  ability  to  use  smaller 
pipe  sizes  for  both  supply  and  return  lines,  with  a  consequent  reduction  in 
cost  of  installation. 

CONSTRUCTION  AND  ARCHITECTURAL  FEATURES:  The  construction  and 
architectural  features  of  the  building  present  a  variety  of  problems. 

It  is  frequently  necessary  to  heat  finished  basement  rooms  by  placing 
the  radiators  under  the  windows  or  at  other  points  near  the  floor.  Under 
these  circumstances  the  condensation  from  the  low  radiators  will  not  return 
to  the  boilers  by  gravity,  as  they  are  located  at  or  below  the  water  line  and 
it  becomes  necessary  to  install  a  vented  receiver  and  an  automatic  return 
pump  or  a  vacuum  pump.  The  former  will  operate  in  conjunction  with  a 
modulation  system,  the  latter  with  a  vacuum  system. 

Frequently  the  structural  conditions  of  the  building  are  such  that  the 
return  piping  has  to  be  run  near  the  ceiling  of  the  basement  or  along  the 
floor  of  the  first  story.  The  lifts  resulting  from  this  situation  make  the 
use  of  a  vacuum  system  imperative.  A  very  high  building  or  one  covering 
a  very  large  area  impose  such  conditions  that  the  vacuum  system  is  again 
the  best  solution  of  the  problem.  The  greater  pressure  differential  which 
results  in  this  system,  enables  the  use  of  smaller  piping  or  with  the  same 
size  piping  reduces  the  back  pressure  which  must  be  carried  in  the  engines  and 
pumps  to  secure  complete  circulation. 

Reference  has  been  made  to  the  use  of  modulation  supply  valves  to 
control  the  quantity  of  steam  delivered  to  the  individual  radiators.  In 
department  stores,  loft  buildings,  warehouses,  factories,  etc.,  where  there 
are  large  open  spaces  to  be  heated,  usually  containing  a  number  of  radiators, 
the  modulation  supply  valves  may  be  omitted  and  a  fair  degree  of  tempera- 
ture regulation  may  be  obtained  by  completely  shutting  off  one  or  more  unit. 

SOURCES  OF  STEAM  SUPPLY  :  There  are  three  main  sources  of  steam  supply : 

1.  Live  steam  from  high-pressure  or  low-pressure  boilers. 

2.  Exhaust  steam  from  engines,  turbines  or  auxiliaries. 

3.  High-pressure  or  low-pressure  steam  from  outside  sources. 

If  steam  is  required  for  heating  purposes  only,  the  selection  of  the  boiler 
will  be  a  part  of  the  heating  problem,  based  upon  the  building  requirements. 
Where  no  mechanical  apparatus  is  necessary,  low-pressure  boilers  will  be 
the  natural  choice.  If  electric-  current  is  not  available  and  the  system 
requires  fan  engines,  return  pumps  or  vacuum  pumps  or  other  power-driven 
apparatus,  a  type  of  boiler  should  be  selected  which  is  capable  of  operating 

103 


\'"\lt.  1(1-1.     <'.nsl-ir<in  wiill  nidiation  arranged  under  the  SHW  tooth  of  H  factory  roof 


V\K.  10-5.     ArrmiKi'iuont  of  rnsl-inm  wiill  rndiiilion  on  side  \\iills  of  ;i  fnc-tor\  building 

104 


successfully  with  a  working  steam  pressure  of  not  less  than  25  to  30  Ib. 

The  conditions  under  which  the  heating  boiler  must  operate  are  to  a 
large  extent  the  governing  factor  in  its  selection.  The  kind  of  fuel,  the 
intensity  of  draft  which  can  lie  obtained,  the  length  of  time  between  firing 
periods,  the  character  of  attention  which  the  boiler  will  receive,  the  abuse 
which  it  will  stand  without  injury,  are  all  important  factors  which  should 
receive  due  consideration. 

The  dimensions  of  the  fire  box,  the  proportion  of  direct  and  indirect 
heating  surface  in  the  boiler,  the  area  and  type  of  grate  and  the  available 
draft  are  all  influenced  by  the  kind  of  fuel  which  is  to  be  burned.  This 
in  turn  depends  upon  the  geographical  location  of  the  plant  and  the  local 
fuel  market.  In  many  cities,  boilers  larger  than  a  given  size  are  required 
to  comply  with  more  or  less  drastic  smoke  prevention  laws.  It  will  thus 
l>c  -ivii  that  the  fuel  plays  a  very  important  part  in  the  choice  of  a  boiler. 

Sufficient  attention  is  not  always  paid  to  selecting  a  boiler  having 
Hues  and  surfaces  perfectly  accessible  for  cleaning.  It  is  also  important 
in  operating  the  boiler  to  see  that  there  is  a  systematic  removal  of  all  soot 
and  dirt  at  regular  and  frequent  periods.  In  parts  of  the  country  where 
the  water  contains  heavy  scale-forming  material,  boilers  having  interior 
pockets  should  be  avoided  as  scale  will  accumulate  easily  in  these  pockets 
and  cannot  be  removed  even  by  more  frequent  blowing  down. 

The  shape  of  the  boiler  room  may  have  some  influence  upon  the  type 
of  lx>iler  selected.  A  long,  narrow  room  may  lend  itself  better  to  the  use 
of  tubular  or  steel  fire-box  boilers,  while  a  nearly  square  space  may  be  best 
adapted  to  the  cast-iron  sectional  pattern.  Where  tubular  boilers  are  selected 
provision  should  be  made  for  ample  space  to  clean  the  tubes  and  to  replace 
them,  when  renewals  become  necessary. 

The  question  of  future  extensions  should  be  considered  when  the  problem 
is  in  the  preliminary  stage.  Unless  provisions  are  made  then,  the  owner 
may  find  it  very  expensive  to  add  to  the  boiler  equipment  at  a  later  date. 

In  buildings  requiring  £4-hr.  heat,  such  as  hospitals  and  like  institutions, 
reserve  units  should  be  installed  to  provide  for  possible  breakdown. 

In  low-pressure  installations,  where  a  part  or  all  of  the  water  is  returned 
by  mechanical  means,  such  as  a  motor-driven  return  pump,  or  a  vacuum 
pump,  it  frequently  happens  that  the  water  is  delivered  intermittently 
and  in  "slugs"  instead  of  continuously;  or  it  may  fail  completely  on  account 
of  interruption  of  the  current.  The  boiler  must  be  of  such  a  type  or  con- 
structed of  such  material  that  it  will  not  be  injured  by  the  sudden  lowering 
of  the  water  line,  even  to  the  dangerous  point.  In  other  words,  the  design 
or  construction  should  lie  chosen  which  will  permit  the  greatest  withdrawal 
of  water  per  inch  drop  in  water  level. 

Priming  of  boiler>  arises  from  a  number  of  causes,  among  which  may  be 
mentioned  grease  and  dirt  within  the  boiler,  impurities  in  the  water,  lack 
of  proper  steam  disengaging  surface,  insufficient  steam  space,  and  too  high 
velocity  of  steam  at  the  boiler  outlets. 

If  a  type  of  boiler  likely  to  produce  priming  must  be  selected  for 
physical  reasons,  the  arrangement  of  the  connecting  piping  must  be  such 
as  to  eliminate  any  possibility  of  trouble  from  this  source. 

1*5 


The  Architect  must  not  lose  sight  of  the  fact  that  a  boiler  used  solely 
for  heating  purposes  lies  idle,  without  a  fire  under  it,  for  a  period  of  from 
four  to  five  months  of  each  year,  depending  somewhat  upon  the  latitude 
and  length  of  the  heating  season.  Recognition  must  be  taken  of  this  fact 
in  selecting  the  kind  of  material  which  is  best  adapted  to  withstand  the  cor- 
rosive action  which  is  likely  to  occur  in  a  damp  basement  room.  If  the 
material  is  subject  to  rust  and  deterioration  when  lying  idle,  it  should 
have  additional  thickness  to  offset  this  action. 

It  seems  hardly  necessary  to  call  attention  to  the  fact  that  boilers 
should  conform  to  all  requirements  of  local  and  State  ordinances,  and  that 
compliance  with  the  Boiler  Code  of  the  American  Society  of  Mechanical 
Engineers  will  ensure  first-class  material  and  construction. 

The  designer  of  the  plant  for  a  residence  is  in  most  cases  confronted 
with  two  conditions  which  decide  the  type  of  boiler  which  he  shall  use: 
first,  smallness  of  the  boiler  room,  and  second,  the  low  head  room  in  the  base- 
ment. Both  suggest  the  use  of  the  cast-iron  type  of  boiler  because  of  its 
compactness  and  low  water  line. 

If  there  are  other  uses  for  steam,  the  type  of  boiler  or  the  source  of 
steam  supply  may  be  definitely  fixed  by  other  considerations  than  the  re- 
quirements of  the  heating  system. 

Most  large  modern  hotels  in  cities  are  provided  with  high-pressure 
boiler  plants,  either  for  generating  their  own  electric  power  or,  in  case 
electric  current  is  purchased,  for  operating  the  pumping  equipment  and 
furnishing  steam  for  kitchen  and  laundry  purposes.  The  vacuum  system 
with  steam-operated  vacuum  pumps  is  proper  for  heating  such  buildings. 

Great  progress  has  been  made  in  recent  years  by  the  country  towns  in 
providing  more  convenient  hotel  accommodations  for  the  traveling  public. 
The  owner  of  the  small-town  hotel,  while  not  in  a  position  to  equip  with 
all  the  refinements  of  a  metropolitan  hotel,  is  anxious  to  have  his  guests 
provided  with  comfortable  and  properly  heated  rooms  and  therefore  wishes 
to  install  an  efficient  and  economical  plant.  The  modulation  system  either 
with  gravity  return  or  with  vented  receiver  and  return  pump  is  particularly 
advantageous,  giving  all  that  can  be  asked  in  heating  effect,  and  enabling  the 
janitor  or  engineer,  who  is  also,  in  many  cases,  the  porter,  bell  boy  and  general 
utility  man,  to  take  care  of  his  many  other  duties. 

Y.  M.  C.  A.  buildings  resemble  the  first  mentioned  type  of  hotels  in 
many  respects,  as  in  addition  to  the  recreational  features,  hotel  accom- 
modations are  provided  for  the  members.  Restaurant  and  cafeteria  service 
are  maintained,  as  well  as  swimming  pools,  Turkish  baths,  etc.,  in  con- 
nection with  which  there  is  a  demand  for  high-pressure  steam  in  addition 
to  the  low-pressure  steam  needed  for  heating.  For  this  reason  all  the  con- 
densation cannot  be  returned  directly  to  the  boilers. 

The  heating  system  should  be  of  a  type  which  permits  regulation  of 
the  supply  of  steam  to  the  bedrooms,  according  to  whether  they  are  occupied 
or  empty.  The  graduated  control  system  of  steam  supply  to  the  radiators 
by  means  of  modulation  supply  valves  is  a  logical  system  to  adopt.  A 
steam-operated  pump  and  receiver  takes  care  of  the  returns  from  all  the 
steam-using  equipment  and  also  from  the  heating  system. 

106 


The  modern  hospital  has  a  considerable  amount  of  steam-using  equip- 
ment such  as  sterilizers,  blanket  warmers,  steam  cookers,  dishwashing 
machines,  laundry  machinery,  etc.,  requiring  steam  at  pressures  ranging  from 
.SO  to  90  Ib.  This  makes  a  high-pressure  boiler  plant  necessary.  Many 
of  the  larger  hospitals  have  their  own  electric  power  plants,  and  also  use 
steam  for  operating  refrigerating  plants.  In  such  cases  the  available  exhaust 
steam  should  lie  utilized  to  the  fullest  extent  and  this  is  best  accomplished 
by  means  of  a  vacuum  system. 

High-pressure  boilers  are  usually  installed  in  manufacturing  plants 
where  high-pressure  steam  is  needed  for  process  work  and  cheap  electric 
power  is  not  available.  In  such  cases  the  necessary  electrical  machinery 
for  generating  current  is  installed  and  the  exhaust  steam  is  used  for  heating. 
As  with  hospitals  and  office  buildings,  the  vacuum  system  ensures  quick 
circulation  of  steam  and  removal  of  air  and  reduces  the  back  pressure  to 
a  minimum.  Where  the  plant  extends  over  considerable  area,  the  use  of 
smaller  size  supply  and  return  mains,  and  the  ability  to  lift  the  condensation 
where  changes  of  grade  occur,  become  important  factors. 

In  localities  where  street  steam  is  available,  with  uninterrupted  service 
guaranteed  for  the  entire  heating  season,  and  where  the  rate  does  not  exceed 
that  at  which  steam  can  be  generated  in  an  individual  plant,  the  installation 
of  the  modulation  system  with  street  steam  supply  provides  very  satis- 
factory heating  for  almost  any  type  of  building. 

The  reduced  first  cost  of  the  heating  plant,  due  to  the  omission  of  the 
boiler  and  its  appurtenances,  and  the  fact  that  such  a  plant  requires  practi- 
cally no  operating  attention,  make  the  arrangement  very  attractive  from 
the  owner's  standpoint . 

The  service  company  supplying  steam  to  the  building  usually  extends 
the  service  pipe  through  the  foundation  wall  and  to  this  the  heating  con- 
tractor makes  his  connection.  The  water  of  condensation  is  discharged  to  the 
sewer  through  a  meter  in  the  return  line,  except  where  a  flat  rate  per  square 
foot  of  radiation  is  charged,  in  which  case  no  meters  are  used. 

This  type  of  heating  system  can  be  installed  in  almost  any  type  or  size 
of  building,  except  where  too  extensive  area  prevents  satisfactory  arrange- 
ment of  the  return  line  for  gravity  open-return  circulation.  In  such  cases, 
the  motor-driven  vacuum  pump  offers  a  simple  means  of  insuring  positive 
removal  of  the  condensation  and  air. 

OPERATION  AND  ATTENTION:  The  initial  cost  is  frequently  the  de- 
ciding factor  in  the  selection  of  a  heating  system,  and  it  is  not  until  the 
end  of  the  first  heating  season,  when  the  purchaser  finds  out  the  cost  of 
fuel  and  caretaker's  services,  that  the  question  of  operation  and  attention 
receives  the  consideration  to  which  it  is  entitled.  In  this  chapter,  however, 
it  is  not  possible  to  more  than  touch  briefly  upon  this  important  subject. 

The  most  successful  heating  system  is  the  one  which  will  accomplish 
all  of  the  results  for  which  it  is  designed  with  the  least  amount  of  attention 
and  the  minimum  expenditure  for  fuel.  With  the  view  of  simplifying  the 
system,  the  use  of  mechanical  devices  for  handling  the  condensation  should 
be  limited  to  those  cases  where  an  open-line  gravity  return  does  not  work 

107 


out  satisfactorily.  The  conditions  under  which  return  pumps  and  vacuum 
pumps  are  necessary  have  been  fully  explained  in  previous  paragraphs  and 
it  is  not  necessary  to  refer  to  the  subject  again. 

We  cannot  emphasize  too  strongly  the  important  part  which  the  radiator 
return  trap  plays  in  the  economy  of  operation.  It  should  be  of  a  type  that  will 
permit  the  rapid  removal  of  all  air  and  all  condensation  but  at  the  same  time 
prevent  the  escape  of  any  steam.  This  point  is  explained  very  thoroughly 
in  Chapter  14. 

A  system  cannot  be  expected  to  give  the  best  results  unless  all  of  the 
operating  conditions  are  favorable.  Three  factors  which  have  a  great 
influence  upon  economical  as  well  as  successful  operation  are  the  location 
of  the  boiler  room,  its  size  and  that  of  the  chimney. 

In  planning  the  basement  of  any  building  the  architect  should  pay 
particular  attention  to  both  the  boiler  room  and  the  coal  and  ash  storage 
spaces.  It  is  needless  to  say  that  the  coal  room  should  be  so  placed  that 
the  labor  of  stowing  away  the  fuel,  and  afterwards  feeding  it  to  the  boiler, 
is  reduced  to  a  minimum,  and  that  suitable  means  is  provided  for  the 
economical  handling  of  ashes. 

Ample  firing  space  must  be  provided  in  front  of  the  boiler,  ample  room 
at  the  rear  to  give  easy  access  to  the  return  and  blow-off  piping  and  walking 
space  at  either  side  wide  enough  to  enable  the  steamfitter  to  easily  and  quickly 
assemble  the  sections  and  later  permit  the  application  of  the  covering. 
If  the  boiler  is  the  tubular  type,  there  must  be  space  for  cleaning  the  tubes 
as  well  as  for  replacing  them  when  repairs  become  necessary. 

Limiting  the  depth  of  the  boiler  room  is  a  false  economy  and  will  only 
result  in  partial  if  not  almost  complete  failure  of  the  heating  system  to  give 
satisfaction.  There  must  be  sufficient  grade  so  that  the  overhead  return 
piping  can  be  given  ample  pitch  toward  the  boilers,  thus  ensuring  quick 
return  of  the  condensation  by  gravity,  and  so  that  the  lowest  point  of  the 
return  for  an  open-return-line  modulation  system  is  at  least  30  inches  above 
the  water  line  of  the  boiler. 

Lack  of  head  room  reduces  the  pitch  of  the  return  piping  to  a  minimum 
and  narrows  the  selection  of  boilers  to  perhaps  a  single  type,  having  a  low 
water  line  but  otherwise  not  at  all  adapted  to  the  work  which  it  must  perform. 
It  may  also  compel  the  construction  of  a  pit,  which  is  not  always  desirable, 
or  require  an  electric  return  pump  which  may  unnecessarily  complicate 
a  system  that  would  otherwise  be  very  simple. 

Certain  types  of  buildings  require  the  simplest  heating  system  possible. 
In  residences  the  firing  is  infrequent  and  is  done  by  the  owner  or  a  caretaker. 
The  system  must  be  rugged  in  design,  with  the  least  possible  mechanical 
devices,  but  flexible  enough  to  respond  to  varying  changes  of  outside  tempera- 
ture and  weather. 

The  janitors  of  school  buildings  have  a  multitude  of  duties  to  perform 
besides  that  of  fireman.  In  the  rural  districts  the  school  committees  have 
limited  appropriations  for  janitor  service  and  apparatus  has  to  be  installed 
which  is  capable  of  giving  satisfactory  results  with  such  unskilled  attendance 
as  is  available. 

108 


As  stated  before,  apartment  houses  are  run  on  a  business  basis  and  the 
heating  system  must  be  economical  of  fuel  and  require  little  attention  but 
must  be  flexible  enough  so  that  the  occupants  have  a  convenient  and  inde- 
pendent means  of  controlling  the  temperature  of  the  various  rooms.  In 
the  various  types  of  buildings  outlined  above,  the  modulation  system, 
with  open  return  line  to  the  boiler,  will  be  found  to  meet  the  requirements  of 
simplicity,  flexibility  and  economy. 

Passing  to  the  combination  of  the  open  return  line  with  either  the 
automatic  return  pump  and  vented  receiver  or  the  vacuum  pump,  or  the 
straight  vacuum  system,  we  find  the  same  economy  and  flexibility  with 
the  addition  of  comparatively  simple  mechanical  return  apparatus. 

Summing  up  the  advantages  of  the  modulation  and  vacuum  system 
we  find  them  to  be  as  follows: 

Modulation   Systems: 

1.  Simple  in  design. 

2.  Efficient  in  fuel. 

3.  No  expert  attendance  required. 

4.  Quick  response  to  demands  for  changes  in  rate  of  heating. 
I'acuum   Systems:     1.   Circulation    of    steam    is    quick,    positive    and 

uniform.     All  surfaces  are  heated  in  a  relatively  short  space  of  time  after 
steam  is  turned  into  the  system. 

2.  Saving  in  operating  cost  is  accomplished  practically  by  eliminating 
back  pressure  upon  steam  engines.     This  either  saves  directly  in  fuel  cost 
or  permits  the  engines  to  do  more  work  at  same  expenditure  of  fuel. 

3.  Saving  is  effected  through  the  ability  during  mild  weather,  when 
demands  for  heating  are  slight,  to  distribute  a  relatively  small  volume  of 
steam  throughout  the  system  as  needed,  with  a  pressure  at  or  even  slightly 
below  the  atmosphere.     In  this  country,  mild  weather  constitutes  about 
75  per  cent  of  each  heating  season,  moderately  cold  weather  about  20  per  cent 
and  only  5  per  cent  can  be  classed  as  "severely"  cold. 

4.  Saving  of  fuel  results  from  utilizing  the  condensation  and  its  con- 
t  ained  heat  as  part  of  the  boiler  feed. 

Certain  advantages  are  common  to  both  systems,  as  follows: 
Modulation   and   Vacuum   Systems:     1.  Noiseless  in  operation.  Water 

hammer  is  unheard  of  due  to  continuous  relief  of  air  and  positive  removal 

of  condensation. 

2.  Radiators  maintained   at    100  per  cent  heating  efficiency  due  to 
complete  removal  of  air  and  water.     Absence  of  air  valves  on  radiators 
eliminates  one  of  the  most  annoying  features  of  many  heating  systems. 

3.  Independent  temperature  control  of  each  room  at  the  will  of  the 
occupant. 

4.  Efficient  in  fuel. 

To  the  foregoing  advantages  should  be  added  comfort  and  convenience. 
More  and  better  work  is  obtained  from  occupants  of  properly  heated 
buildings. 


109 


CHAPTER  XI 

Flow  of  Low- Pressure  Steam  Through  Piping 

FLOW  OF  STEAM  THROUGH  PIPES:  Flow  of  steam  through  piping  is 
caused  by  difference  in  pressure,  which  diminishes  continually  from 

the  source  to  the  outlet,  due  to  frictional  resistance,  deflection,  con- 
traction and  expansion.  Likewise  there  is  a  continual  drop  in  temperature 
due  to  the  transmission  of  heat  through  the  walls  of  the  piping. 

Steam  at  initial  pressure  and  density,  but  without  material  velocity,  as 
in  a  boiler,  requires  a  certain  pressure  drop,  to  impart  initial  velocity  in  the 
main.  This  drop  varies  with  the  velocity  required,  density  of  steam  and 
shape  of  the  orifice  at  entrance  of  the  main.  The  pressure  drop  or  head 
required  for  a  given  velocity,  as  of  initial  density  at  a  point  about  three 
diameters  beyond  the  entrance  of  a  steam  main,  with  sharp  entrance  edge, 
has  been  found  from  tests  of  the  weight  of  low-pressure  steam  passing 
through  a  cylindrical  sharp-edged  orifice  of  length  equal  to  three  diameters. 
The  pressure  difference  or  head  (hi)  necessary  to  produce  such  velocity 


is  fully  1.7  times  that  found  by  the  well  known  velocity  formula,  v  =  V2  gh. 

It  seems  reasonable  to  assume  that  a  like  pressure  drop  is  necessary  to 
impart  initial  velocity  within  the  heating  main  from  a  boiler  or  steam  drum, 
as  contrasted  with  the  exhaust  of  an  engine,  reducing  valve,  etc. 

Table  11-1  gives  1.7  times  the  pressure  drop  or  head  (hi)  in  pounds 
and  ounces  per  square  inch,  based  on  the  above  assumption. 

Table  11-1.     Velocity  of  Steam  in  Feet  per  Minute  Within  Entrance  of  Main    (as  of 

Initial   Density)    Produced   by  Pressure  Drop    (P! — p2)=h 

From  various  absolute  initial  pressures  in  pounds  per  sq.  inch=pj 

PI-DO  Pi-Pi  Velocity  in  feet  per  minute 

Ounces  Pounds 


per  sq.  per  sq.  Absolute  initial  pressure  p 

inch  inch  15  16  17  18  19  20 


.01 

2260 

2203 

2138 

2086 

2036 

1980 

x 

.0156 

2830 

2758 

2665 

2610 

2544 

2475 

.02 

3200 

3115 

3020 

2950 

2880 

2800 

Yi 

.0312 

3995 

3885 

3770 

3680 

3595 

3495 

.04 

4530 

4405 

4270 

4175 

4070 

3960 

X 

.0468 

4910 

4775 

4625 

4520 

4420 

4280 

.05 

5060 

4930 

4780 

4660 

4540 

4420 

1 

.0625 

5660 

5520 

5340 

5220 

5090 

4950 

.07 

6000 

5840 

5660 

5520 

5390 

5240 

IX 

.0781 

6350 

6180 

5980 

5840 

5710 

5540 

.08 

6420 

6240 

6050 

5910 

5770 

5610 

.09 

6800 

6615 

6410 

6260 

6120 

5940 

l,'/2 

.0937 

6940 

6750 

6540 

6390 

6250 

6060 

.1 

7170 

6980 

6760 

6610 

6460 

6260 

.11 

7520 

7320 

7090 

6925 

6770 

6570 

.12 

7860 

7650 

7420 

7240 

7060 

6870 

2 

.125 

8020 

7810 

7560 

7390 

7220 

7010 

.13 

8180 

7960 

7710 

7520 

.   7350 

7150 

.14 

8470 

8250 

7990 

7800 

7610 

7410 

.15 

8790 

8560 

8290 

8090 

7910 

7680 

•^A 

.1562 

8970 

8740 

8460 

8760 

8080 

7840 

no 


Friction  in  Run:  Steam,  having  attained  initial  velocity  at  the  entrance 
of  the  main  by  a  pressure  drop  (p,  —  p2),  will  require  a  further  drop  (p2  —  p3) 
to  overcome  friction. 

Various  formulae  have  been  published  by  which  to  determine  the 
velocity  or  weight  of  steam  of  given  quality  which  with  a  given  pressure 
drop  will  flow  in  a  given  time  through  a  given  length  of  straight  pipe  of 
given  uniform  diameter. 

Analysis  of  the  principal  formulae,  after  reduction  to  common  terms, 
indicates  a  substantial  agreement  among  the  majority  of  these  formulae 
n  the  following  fundamentals: 

that,  the  velocity  varies  as  the  square  root  of  the  pressure  drop. 

that  the  velocity  varies  as  -3    — r— 

density 

that  the  pressure  drop  varies  as 


density 

that  the  pressure  drop  is  proportional  to  length  of  run. 
that  the  pressure  drop  varies  as  the  square  of  the  weight  flowing. 
The    various  •  fundamental    equations    for   frictionless    pipes    may    be 
reduced  to  the  following  form: 


w  = 


> 


(P*  "  P')  r 

p 


and  the  allowance  made  for  friction  by  multiplying  the  radical  by  a  constant 
or  numerical  value,  dependent  on  the  diameter,  in  the  following  form: 


w  =  e 


(Pt  "  P')  -  d' 


V  xL  or  (L  +  y) 
in  which 

\v    =  weight  of  steam  flowing  per  minute. 

c     =  a  constant  or  numerical  value 

PI    =  absolute  pressure  of  initial  steam  when  quiescent. 

p»    =  absolute  pressure  within  entrance  of  main. 

p3   =  absolute  pressure  near  end  of  main. 

d     =  diameter  in  inches. 

L    =  length  of  run  in  feet. 

x     =  a  factor  of  L  derived  from  some  sub-formula. 

y     =  a  formula  or  sum  to  be  added  to  L  in  the  basic  equation. 

=  mean  weight  of  1  cu.  ft.  of  steam  in  pounds. 

Regarding  the  value  of  c,  the  late  Professor  Kent  made  the  following 
apt  statement: 

'The  coefficient  of  friction  according  to  different  authorities  varies 
according  to  laws  about  which  they  do  not  agree." 

Investigation  demonstrates  that  many  of  the  laboratory  experiments 
and  tests  of  commercial  pipe  lines  upon  which  the  values  of  c,  x  and  y  have 

in 


been  estimated  were  so  made  as  to  include  the  pressure  drop  necessary  for 
initial  velocity  while  in  others  this  is  not  included.  Other  tests  appear 
to  have  been  made  on  but  one  or  at  best  a  very  few  different  sizes  of  pipe 
and  lengths  of  run. 

Some  authorities  assume  that  the  factor  c  (which  includes  all  friction) 
is  constant  for  all  sizes  of  pipe  irrespective  of  relation  of  perimeter  to  in- 
cluded area  of  cross  section;  in  this  respect  differing  materially  from  all  the 
commonly  accepted  formulae  for  flow  of  water.  These  among  themselves 
assign  materially  different  constant  values  to  c. 

Other  authorities  assign  values  varying  with  diameter,  thereby  recog- 
nizing the  proportionate  relation  of  perimeter  to  cross-section  and  the  in- 
fluence of  surface  retardation  on  the  flowing  mass.  The  two  principal 
investigators  of  the  latter  school  do  not  differ  materially  in  the  values  assigned 
to  c  although  J.  M.  Spitzglass,  in  his  analysis,*  goes  exhaustively  into 
the  frictional  elements  (skin  friction  due  to  rubbing  of  the  fluid  on  the  rough 
surface  of  pipe  and  internal  friction  due  to  relative  motion  of  particles  of 
fluid  on  each  other)  and  deduces  a  formula  which  takes  into  consideration 
both  the  coefficient  of  friction  and  the  relative  capacity  of  pipes  of  various 
diameters  together  with  experimental  coefficients  for  the  various  fluids. 

Gebhart  in  his  analysis  of  this  subject  makes  the  following  very  practical 
statement: 

"Notwithstanding  the  numerous  investigations  conducted  on  labora- 
tory apparatus  and  on  pipe  lines  under  actual  power  plant  conditions,  there 
is  no  trustworthy  rule  for  accurately  determining  the  flow  of  steam  in 
commercial  piping." 

Professor  R.  C.  Carpenter  in  his  investigations  regarding  flow  of  steam 
in  pipes  reaches  the  following  conclusion  : 

"For  practical  conditions,  it  is  rather  better  to  have  an  allowance 
in  pipes  for  an  excess  in  friction  than  to  have  the  reverse  condition  true." 

From  an  extended  experience  in  steam  heating  practice  and  installation, 
it  seems  a  fair  conclusion  that  in  none  of  the  published  formulae  is  sufficient 
consideration  given  to  the  excess  friction  liable  to  be  encountered  due  to 
reduction  in  area  and  frictional  resistance  due  to  the  very  usual  neglect  of 
the  workmen  to  ream  pipes  true  after  cutting. 

This  excess  friction  is  likely  to  increase  as  the  proportion  of  perim- 
eter to  area  increases  and  be  a  serious  source  of  inaccuracy  in  the  deter- 
mination of  flow  in  the  smaller  sizes  of  commercial  piping,  and  pipes  if 
inadequate,  when  once  installed,  will  usually  remain  a  source  of  trouble 
and  discredit. 

This  has  led  to  the  use  of  a  table  in  which  the  value  of  c  in  the  formula 


^ 

"  s 


has  been  increased  for  the  smaller  sizes  beyond 


__ 
\          L 
that  of  any  of  the  authorities  above  referred  to. 

These  values  of  c  and  the  flow  table  based  thereon  are  offered  as  those 


*  Flow  of  Fluids  and  Fridional  Resistance  in  Pipes,  J.  M.  Spit/glass,  Armour  Engineer,  March  and 
May,  1917 

112 


found  to  be  adequate  in  practice  under  any  but  the  worst  practical  con- 
ditions to  which  it  has  been  applied. 


W  =  60c 


> 


-  Pi)    ~db 


(Formula  11-1} 


=  weight  of  steam  in  pounds  per  hour. 

"  1"        li"        1J"        2"        2J"        3"        3J"        4" 

Valueofc  31          41          44         49        52        55.6        57         59        61       62.5      63.4 

Value  of  ••  61.2        64.8        65.4  66  65  65  65  65 

This  formula   makes  no  allowance  for  drop  due  to  initial  velocity, 

condensation,  or  changes  in  direction  or  area  of  pipe. 

Table  11-2,  Pages  114-5,  has  been  computed  from  Formula  11-1 

For  example,  ascertain  the  pressure  necessary  to  overcome  friction 

in  a  400-ft.  run  of  4-in.  straight  pipe  when  conveying  600  Ib.  of  steam  per 

hr.  and  p2  is  16  Ib.  per  sq.  in.  absolute. 

=  (0.821)-  =  0.674  Ib.  pressure  drop  for  1000  ft.  due  to  weight  of 

steam  other  than  tabulated;  therefore,  pressure  drop  for  given  length,  or 
400  feet  is: 


0.674  (  Y/V  K  )  =  0.270  Ib.  per  sq.  inch. 


V 10007 

Condensation  Loss:  Through  the  entire  length  of  run,  there  is  a  further 
loss  of  pressure,  due  to  radiation  and  condensation.  This  loss  is  least  in 
well  covered  mains  with  still  air,  at  high  temperature.  Condensation  in 
long  runs  of  small  pipe  frequently  causes  the  greatest  loss  of  weight  and  oc- 
casions large  pressure  drop. 

Figure  11-1,  Page  116,  gives  averages  of  condensation  loss  in  bare  and 
covered  pipes  for  various  differences  between  temperature  of  steam  in  pipe 
and  air  surrounding  the  pipe  or  its  covering. 

The  following  example  is  given  to  call  attention  to  what  is  likely  to 
happen  if  tabular  steam  values,  for  straight  runs,  be  used  to  size  mains  sup- 
plying radiation  through  long  runs  of  small  pipe,  even  if  the  mains  are  well 
insulated.  From  Table  11-2  it  will  be  seen  that  a  l^-in.  pipe  with  a  friction 
loss  of  1/10  pound  per  100  ft.  and  an  initial  pressure  of  16  Ib.  absolute  will 
convey  steam  at  an  hourly  rate  of  55.1  Ib.  or  53250  B.t.u.  per  hour. 

By  inspection  of  Figure  11-1,  we  find  that  if  the  difference  in  tempera- 
ture between  steam  in  the  pipe  and  air  surrounding  it  is  150  deg.  fahr. 
and  the  pipe  has  good  insulation,  there  is  transmitted  through  that  cover- 
ing about  25  B.t.u.  per  lin.  ft.  (J^  sq.  ft.),  or  25000  B.t.u.  per  hour  for  1000 
ft.  run.  Therefore,  about  60  per  cent  of  the  entering  steam  will  be  con- 
densed. 

Effect  of  Deflection,  Contraction  and  Expansion:  Mains  are  seldom 
straight  cylindrical  pipe  from  end  to  end.  Normally  there  are  elbows, 
valves,  branch  outlets,  reductions  in  size,  separators,  expansion  joints,  etc., 

113 


each  adding  to  frictional  resistance  and  causing  pressure  drop. 

Although  not  technically  accurate,  it  has  been  found  convenient  in 
estimating,  to  express  these  resistances  in  units  of  the  additional  length  of 
run  of  straight  pipe  that  would  produce  an  equal  effect.  Table  11-3,  which 
is  believed  to  be  conservative  and  likely  to  produce  results  well  within  the 
tolerance  necessary  in  so  complicated  a  subject,  is  figured  upon  this  basis. 

Fittings  of  different  manufacturers  vary  in  resistance  in  similar  sizes 
and  similar  fittings  vary  in  percentage  of  resistance.  No  very  careful 
tests  covering  the  entire  range  of  flow  of  water,  air  and  steam  are  available 
for  data,  but  those  that  do  exist  have  been  studied  in  making  up  this  table. 

PRESSURE  DROP:  The  necessity  for  pressure  drop  to  create  flow  in 
heating  systems  is  further  explained  in  following  pages.  Modulation  and 
vacuum  systems  differ  in  degree  of  this  pressure  drop  rather  than  in  principle. 

Table  11-2.    Weight  of  Steam  Flowing  Uniformly  in  One  Hour  Through  Standard 

Straight  Level  Pipes  1000  ft.  Long,  with  a  Loss  of  1  Ib.  per  Sq.  In., 

from   Given   Initial  Pressure   Within   Inlet   End 

P2=absolute  initial  pressure  within  entrance  of  main.  r  =  latent  heat  of  steam  at  absolute  initial 
pressure  V^.  1000  B.t.u.  =  thousands  of  B.t.u.  contained  in  the  entering  steam.  V  =  velocity 
of  steam  in  feet  per  min.  at  initial  density 


Nominal 
size  | 

Actual  internal 
dia.  in  inches 

Actual  outside 
dia.  in  inches 

Linear  ft. 
per  cu.  ft.  of 
internal  volume 

Actual  inside 
area  in  sq.  in. 

Linear  ft. 
per  sq.  ft.  of 
external  surface 

Sq.  ft.  of 
ext.  surface 
per  linear  ft. 

Actual  internal 
(Dia.):! 

Constant  C 
in  formula 

PJ 

15 

16 

17 

18 

19 

20 

s 

26.27 

24.79 

23.38 

.04277 

22.16 
.04512 

21.07 

20.08 

i 

S 

.03806 

.04042 

.04746 

.04980 

r 

969.7 

967.6 

965.6 

963.7 

961.8 

960 

1" 

1.019 

1.315 

167.5 

.86 

2.9 

.  345 

1.13 

34 

Lb. 
1000  B.t.u.  - 
Vel.  ft.-min. 

14.2 

13.7 
1044 

14.63 
14.15 

1001 

15.08 
14.5 
983 

15.48 
119 
955 

15.88 
15.27 
934 

16.23 
15.6 
908 

11" 

1.38 

1.66 

96.1 

1.5 

2.3 
2.01 
1.61 
1.33 

.  43  1 

2.235 
3.28 

41 
44 

Lb. 
1000  B.t.u. 
V 

33.9 
32.8 
1428 

34.92 
33  .  75 
1385 

35.92 
34.7 
1344 

36.90 
35.5 
1310 

37.86 
36.4 
1276 

38.80 
37.3 
1248 
61.1 
58.7 
1444 

li" 
2" 
2J" 

1.61 
2.067 

1.9 
2.375 

70.6 

2.01 

.197 

Lb. 
1000  B.t.u. 
V 

53.4 
51.7 
1650 

55.1 
53.25 
1607 

56.6 
54.6 
1554 

58.2 
56 
1518 

59.65 
57.3 
1478 

12.9 

3.36 
4.78 

.621 

6.13 

49 

Lb. 
1000  B.t.u. 
V 

111.2 
107.9 
2082 

114.5 
110.8 
2022 

117.7 
113.5 
1960 

121 
116.4 

1906 

121.2 
119.5 
1865 

127 
122 
1820 

2.469 

2.875 

30.15 

.751 

9.58 

52 

Lb. 
1000  B.t.u. 
V 

184.1 
178 
2432 

1  89  .  -2 
182.9 
2353 

195.2 
188.3 
2295 

201  .  5 
194 

2240 

205 
197 
2170 

211 
202.5 
2130 

3" 

3.068 

3.5 

19.5 

7.39 

1.09 

.991 

16.47 

55.6 

Lb. 
1000  B.t.u. 
V 

339 
328.5 
2890 

349 
337.5 
2808 

359 
347 

2725 

369.5 
356 
2660 

378 
363 
2595 

387 
372 
2530 

3|" 

3.548 
4.026 

4 

14.58 

9.89 

.955 

1.046 

23.7 

57 

Lb. 
1000  B.t.u. 
V 

500 
185 
3190 

515 
498 
3095 

530 
512 
3010 

545 

524 
2925 

558 
537 
2860 

572 
549 
2790 

4" 

4.5 

11.3 

12.73 

.849 

1.177 

32.53 

59 

Lb. 
1000  B.t.u. 
V 

710 
688 
3520 

731 
706 
3415 

752 
725 
3315 

774 
745 
3235 

794 
763 
3155 

812 
779 
3075 

5" 

5.047 

5.563 

7  22 

19.99 

.686 

1.457 

57.17 

61 

Lb. 
1000  B.t.u. 
V 

1  290 
1250 
4070 

1328 
1284 
3950 

1368 
1322 
3835 

1405 
1350 
3740 

1  III) 
1385 
3610 

1475 
1420 
3550 

6" 

6.065 

6.625 

4.99 

28.89 

.577 

1.733 

90.6 

62.5 

Lb. 
1000  B.t.u. 
V 

2091' 
2025 
1565 

2158 
2085 
4440 

2218 
2110 
4300 

2280 
2190 
4195 

2:!10 
2250 
11(10 

2392 
2295 
3980 

7" 

7.023 

7.625 

3.72 

38.74 

.501 

2 

130.7 

63.4 

Lb. 
1000  B.t.u. 
V 

3065 
2970 
5000 

3155 
3050 
4845 

3250 
3140 

1710 

3340 
3210 
4580 

3  I2o 
3290 
1  17.-> 

3506 
3365 
4360 

114 


Table  11-2—  Continued 


Nominal 
size 

Actual  internal 
Dia.  in  inches 

Actual  outside 
dia.  in  inches 

Linear  ft. 
per  cu.  ft.  of 
internal  volume 

Actual  inside 
area  in  sq.  in. 

Linear  ft. 
per  sq.  ft.  of 
external  surface 

Sq.  ft.  Of 

ex.  surface 
per  linear  ft. 

Actual  internal 

Dia. 

Constant  C 
in  formula 

PJ 

15 

16 

17 

IK 

19 
21.07 

20 
2008 

S 

26.27 

2470 

2338 

22.16 
04512 

i 
S 

03806 

.04042 

.04277 

.04746 

.04980 

r 

969.7 

9676 

965.6 

963.7 

961.8 

960 

8" 

7  981 

8.625 

2  88 

50.02 

.443 

2  257 

180 

64.2 

Lb. 
1000  B.t.u. 
V 

4275 

4140 
5380 

4400 

4260 

.-,210 

4530 
4375 
5080 

4652 

4480 
1950 

4775 
4580 
1830 

4485 

4690 
4720 

9" 

8.911 

9.625 

2  29 

62.72 

.397 

1'  5« 

239 

64  8 

Lb. 
1000  B.t.u. 
V 

:,;:!.-, 
5560 
5760 

5900 
5710 
5600 

6075 
5860 
5440 

6240 
6005 
5290 

(,100 

6150 
5175 

6560 
6310 
5050 

10" 

10.02 

10.75 

1  83 

78.82 

.  355 

2.82 

317.7 

65.1 

Lb. 

1000  B.t.u. 
V 

7680 
7440 
6150 

7930 
7660 
5880 

8115 
7870 
5790 

8360 
8010 
5640 

8600 
8270 
5530 

8800 
8450 
5380 

12" 

12 

l2.7.-> 

1.27 

113.1 

.299 

3.3 

198.8 

66 

Lb, 
1000  B.t.u. 
V 

12170 
11750 
6800 

12530 
12120 
6600 

12900 
12460 
6410 

13270113620 
12750  13100 
6230    6100 
20080  20580 
19300  19780 
6700    6510 

13940 
13360 
5910 

14" 

11.25 

15 

.901 

159  5 

.  255 

3.90 

766.5 

65 

Lb. 
1000  B.t.u. 
V 

18420 
17850 
7290 

18970 
18310 
7060 

19520 
18820 
6800 

21  100 
20250 
6400 

16" 

15.5 

17.5 

16 

.  765 

188.3 

.239 

t  16 

945.9 

65 

Lb. 
1000  B.t.u. 
V 

22750 
22050 
763(1 

23110 
22620 
7410 

24100 
23250 
7190 

21800 
23900 
7020 

25150 
21150 
6810 

26100 
25100 
6660 

18" 

20" 

18 

.601 

210 

.212 
.191 

4.71 

1281 

65 

Lb. 

1000  B.t.u. 
V 

30850 
29940 
8100 

31750 
30700 
7850 

32700 
31650 

7650 
12800 
11300 

H050 

33550 
32300 

7125 
1  1000 
12300 
7850 

3  1  150 
33150 
7270 

35250 
33850 
7060 

19.5 

20 

.483 

298 

5.23 

1679 

65 

Lb. 
1000  B.t.u. 
V 

I0:>,00 
39200 
8550 

41600 
40200 
8310 

15200 
13100 
7660 

46250 
14100 

7175 

The  pressure  drop  for  lengths  other  than  1000  ft.  will  be 


1000 


the  tabular    pressure 
1000 


where  LI  is  the  new  length  in  feet,  and  the  weight  of  steam  discharged  will  be  J1Q01 
given  above.  \   LI 

The  pressure  drop  varies  as  -r 7—      The  pressure  drop  varies  as  the  (weight)2. 

The  weight  of  steam  flowing  varies  as  v'  pressure  drop. 


drop, 
X  the  discharge 


Table  11-3.    Resistance  of  Fittings  in  Feet  of  Straight  Pipe  to  be  Added  to 

Actual  Length  of  Run 


Long  sweep 

Medium 

Standard 

Size  of  pipe 
in  inches 

Gate  valve 

ell 
run  of 
standard 

sweep  ell 
reduced 
run  of 

ell 
much 
reduced 

Angle 
valve 

Short 
bend 

Side 
outlet 
tee 

Globe 
valve 

tee 

tee 

tee 

Length  in  feet  to  be  added  in  run 

2 

2 

3 

4 

5 

9 

11 

17 

19 

2y2 

3 

4 

5 

7 

12 

15 

21 

26 

'A 

3 

5 

6 

10 

16 

19 

27 

33 

3K 

4 

6 

8 

12 

19 

22 

32 

39 

4 

5 

7 

9 

14 

22 

24 

36 

45 

5 

7 

9 

11 

18 

27 

30 

44 

58 

6 

9 

11 

14 

22 

32 

36 

51 

70 

7 

10 

13 

17 

26 

37 

41 

56 

82 

8 

12 

15 

20 

31 

42 

47 

63 

94 

9 

13 

17 

22 

35 

47 

52 

68 

104 

10 

15 

20 

24 

39 

52 

57 

76 

117 

12 

18 

24 

30 

47 

62 

68 

91 

140 

14 

20 

26 

33 

53 

71 

79 

105 

160 

115 


01 

/ 

1 

J 

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5  260 

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IT 

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«    10 

// 

,x 

X 

et>       _ 

£ 

x' 

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B.t.u.  Radiation  per  Hour  per  Sq.  Ft.  of  Pipe 

Fig.  11-1.     Heat  transmission  in  B.t.u.  per  hour  per  square  feet  of  bare  and  covered  pipe 

Pressure  Drop  in  Modulation  Systems:  The  typical  modulation  system, 
as  illustrated  in  Figure  11-2,  when  operating  at  normal  rate,  requires  suffi- 
cient pressure  against  the  valve  piece  of  the  vent  valve  pi  to  cause  it  to 
open  against  the  atmospheric  pressure.  Representing  atmospheric  pressure 
as  p  and  this  excess  pressure  as  pi  the  expressions  p  +  PI  =  pressure  at  en- 
trance of  vent  valve. 

116 


Steam  Riser 
leturn  Riser 


*—  -Supply  Valve 


Fig.  11-2.    Diagram  of  modulation  system  layout  to  illustrate  pressure  drop 

To  cause  the  air  to  flow  from  the  vent  trap  through  the  vent  valve 
orifice  requires  a  pressure  difference,  which  may  be  represented  by  p2,  vary- 
ing with  velocity  of  flow.  Therefore,  pressure  in  the  vent  trap  becomes 
=  p  +  PI  +  PS-  To  cause  the  air  to  flow  from  outlet  of  the  radiator  trap 
through  return  main  to  the  vent  trap,  there  must  be  another  pressure 
difference,  represented  by  p3,  dependent  on  velocity  of  flow;  also  another 
pressure  difference  through  orifice  of  radiator  trap  p«.  Therefore,  pressure 
p&  in  the  radiator  at  the  time  of  air  displacement  by  steam  from  the  boiler 
must  equal  the  sum  of  p4  +  ps  +  p2  +  pi  +  p.  Of  these  last  expressions 
p  is  relatively  constant  with  gauge  at  zero  Ib.  The  flow  through  the  vent  valve 
PI  is  nearly  constant,  being  mainly  that  pressure  difference  necessary  to 
overcome  the  gravity  of  the  valve  piece,  and  adhesion  of  wet  surfaces  of  the 
seat.  The  variable  due  to  the  volume  of  air  passing  is  so  slight,  owing  to 
low  velocity,  that  it  may  usually  be  neglected. 

The  pressure  pi  of  vent  valve  suitable  for  a  modulation  system  is 
TV  Ib.  per  sq.  in. 

The  pressure  drop  through  vent  valve  orifice  p2  is  a  variable,  greatest 
during  initial  heating-up  period  when  a  large  volume  of  cool  air  is  expelled 
from  the  heating  system,  and  least  during  normal  heating  when  velocity 
is  that  slight  amount  due  to  entrained  air  in  condensation  passing  from  the 
radiation.  Air-vent  traps  are  rated  on  basis  of  flow  of  initial  air  in  40  min- 
utes in  a  system  with  ,V  Ib.  per  sq.  in.  differential  pressure  through  the 
vent- trap  valve. 

For  less  than  rated  capacity,  either  the  time  or  pressure  factor  or  both 
may  be  less;  for  instance,  with  p2  constant,  one-half  the  amount  of  radiation 
would  require  one-half  the  time  period. 

117 


The  pressure  drop  in  the  return  main  p3  is  also  a  variable,  greatest 
during  initial  heating  and  dependent  on  length  of  run  and  maximum 
velocity.  In  a  well-proportioned  system,  p3  should  never  exceed  1/20  Ib. 
per  sq.  in.  differential  between  the  farthest  radiator  trap  and  the  vent  trap, 
and  during  normal  heating  it  is  so  slight  as  to  be  almost  negligible. 

The  pressure  drop  through  a  radiator  trap  p4  is  also  a  variable,  least 
and  almost  negligible  during  initial  expulsion  of  air  from  radiation,  at  which 
time  the  trap-valve  orifice  is  wide  open.  As  the  radiator  warms  up  and  con- 
densation flows  through  the  trap  orifice  with  the  last  of  the  contained  air, 
p4  gradually  becomes  greater.  It  becomes  maximum  when  condensation  at 
or  near  steam  temperature  is  flowing  at  the  full  rating  of  the  return  trap 
for  a  given  p4  of  Y%  Ib.  per  sq.  in.,  which  pressure  has  been  selected  from 
tabular  ratings  of  return  traps  (page  238).  It  is  good  practice  not  to  have 
p4  exceed  ^  Ib.  per  sq.  in.  where  it  is  advisable  to  carry  less  than  Yi  Ik. 
pressure  on  the  boiler  and  }/±  Ib.  where  a  pressure  of  1  or  2  Ib.  can  be  carried. 

Representing  the  pressure  difference  necessary  for  flow,  initially  of  air 
and  subsequently  of  steam,  from  the  radiator  branch  through  the  inlet  or 
modulation  valve  to  the  radiator,  requires  another  variable  p6,  Y%  Ib.  per 
sq.  in.  at  full  rating,  least  (in  a  properly  designed  modulation  valve  full 
open) ,  during  initial  expulsion  of  air,  and  greatest  when  the  valve  is  partly 
closed  for  modulation  effect,  at  the  selected  rating  of  this  valve,  for  a  given 
pressure  difference  pe. 

p7  is  usually  assumed  for  a  system  of  mains,  risers,  branches  and  run- 
outs, designed  from  data  on  flow  of  steam  in  mains  given  in  Table  11-8 
to  carry  the  maximum  normal  quantity  of  steam  in  a  given  time  from  the 
main  heat  pipe  near  the  boiler  to  the  inlet  valve  of  farthest  radiator,  with 
this  pressure  drop  p7. 

The  quantity  of  steam,  referred  to  in  the  preceding  paragraph,  flowing 
through  the  selected  size  main  supply  pipe  will  have  velocity  at  the  boiler 
which  depends  upon  the  pipe  area  and  the  volume  of  steam  flowing  in  unit 
of  time.  To  impart  this  velocity  to  the  steam  from  a  state  of  quies- 
cence in  the  steam  space  of  the  boiler  and  to  offset  the  resistance  of  the 
orifice  requires  another  pressure  drop  p8.  Knowing  the  maximum  normal 
quantity  of  steam  and  the  size  of  the  main,  the  pressure  drop  to  give  the 
resulting  velocity  can  be  obtained  from  Table  11-1. 

It  follows  from  consideration  of  the  above  that  the  pressure  in  the  boiler 
Pb  at  time  of  maximum  normal  heating  effect  must  be  the  sum  of  p  +  pi  +  p2 
etc.,  including  ps  as  follows: 

I 

p,  constant  at  atmospheric  pressure. 
PI,  at  least  intermittent  at  that  time. 
p2,  negligible  at  that  time. 

p3,  negligible  at  that  time  if  return  has  proper  grade. 
p4,  tabular  if  full  rated  value  in  radiation  is  on  farthest  unit. 
p5,  pressure  drop  in  radiator,  negligible  at  that  time. 
p6,  tabular  if  full  rated  value  in  radiation  is  on  farthest  unit. 
p7,  from  assumption  in  design  from  flow  of  steam  in  main.     (Table  11-8). 
p8,  that  required  for  velocity  head  under  above  assumption.     (Table  11-1\ 

us 


The  heating-up  period  will  vary  in  accordance  with  initial  pressure  in 
the  source  of  steam  supply.  Usually  some  time  is  required  to  raise  steam  to 
the  normal  pressure  Pb.  During  that  time  air  will  be  expelled  and  steam 
flow  into  the  radiation  at  different  rates  due  to  the  varying  pressure  caused  by 
the  increasing  resistance  of  p,  +  p8.  If  steam  is  constantly  supplied  during 
the  heating-up  period  at  pressure  Pb,  as  when  a  central  plant  is  the  steam 
source,  the  condensation  rate  in  the  radiation  due  to  absorption  of  heat 
I >>  the  metal  will  be  as  far  in  excess  of  normal  as  the  sum  of  maximum 
PI  +  PS  +  p»  +  an  intermediate  p4,  deducted  from  Pb  --  p,  will  produce 
a  pressure  difference  (pd)  to  cause  initial  velocity.  It  will  flow  through 
mains  at  a  rate  substantially  in  the  same  proportion  as  pd  is  to  p7,  provided 
initial  velocity  equal  to  ps  has  been  previously  imparted  to  the  steam  within 
the  entrance  of  the  main. 

The  intermediate  p4  referred  to  in  the  above  paragraph  is  caused  by 
tin-  partial  extension  of  the  thermostatically  moved  valve  piece  in  the  return 
trap.  This  factor  varies  from  full  open  and  minimum  resistance,  when 
si  cam  is  first  admitted  and  chilled  condensation  commences  to  pass,  to 
nearly  closed  position  and  full  resistance,  when  the  radiator  is  completely 
filled  up  to  the  return  trap  with  steam  at  a  temperature  corresponding 
with  its  pressure. 

Modulation  systems  when  operated  at  less  than  normal  condensation 
may  circulate  continuously  at  pressure  materially  lower  than  the  normal 
Pb,  or  may  be  intermittently  operated  at  a  pressure  less  than  p,  provided  the 
air  has  first  been  expelled  by  a  higher  operating  pressure.  Under  such 
conditions,  however,  the  system  will  gradually  become  air-bound  and  cease 
to  circulate. 

In  designing  modulation  systems,  all  gravity  drip  points  should  be  pro- 
vided with  a  hydraulic  head  (Hi)  of  at  least  2^£  feet  for  each  pound  per 
square  inch  of  p7  +  pa  +  frictional  resistance  in  run  of  gravity  drip  and  re- 
sistance of  check  valve  between  gravity  drip  and  boiler,  when  the  boiler  is 
generating  steam  at  its  full  capacity  to  supply  cold  radiation. 

If  the  gravity  drip  be  taken  from  radiation  located  below  the  dry  re- 
turn, with  thermostatic  air  vent  up  to  the  dry  return,  then  the  resistance  of 
any  additional  branch  main,  radiator,  valve  and  check  valve  on  gravity  drip, 
must  be  added  to  p7  +  p6,  etc.,  given  above,  to  determine  whether  H2  is 
sufficient. 

The  hydraulic  head  in  inches  of  water  on  the  check  valves  will  vary 
with  the  make,  weight  and  angle  of  the  clapper  and  the  size  of  pipe  tapping. 
This  head  is  seldom  less  than  3  in.  with  the  clapper  at  an  angle  of  10 
deg.  from  vertical  and  may  run  up  to  18  in.  and  higher  with  vertical-lift 
valve  pieces. 

In  installing  radiation  with  gravity  drip  for  condensation  as  above,  it  is 
important  that  the  branch  connections  and  valve  to  such  radiation  have 
sufficient  free  area  when  in  use,  to  cause  little  or  no  reduction  in  pressure  in 
the  radiator,  from  that  in  the  main.  A  partially  closed  inlet  valve  might 
cause  such  a  reduction  in  pressure,  when  added  to  the  other  resistances,  that 
there  would  not  remain  sufficient  total  pressure  in  the  radiator,  when  added 
l<>  the  available  H2,  to  overcome  the  pressure  Pb  plus  the  check  valve  resist- 
no 


ance  in  gravity  drip.  In  consequence  of  this,  condensation  would  build  up 
in  the  column  H2,  seal  the  radiator  outlet  and  finally  cause  the  radiator  to 
become  water-logged,  possibly  draining  at  a  partial  condensation  rate, 
through  the  air  vent  into  the  dry  return  line. 

The  closing  level  of  the  air-vent  trap  should  be  located  at  such  a  height 
above  the  water  line  of  the  boiler  that  a  hydraulic  column  is  produced  fully 
equal  to  the  resistance  of  its  check  valve  and  drain  pipe  plus  normal  Pb. 

This,  however,  is  not  as  important  as  to  have  HI  and  H2  ample.  An 
air  pressure  will  accumulate  in  this  vent  trap  due  to  closing  of  the  vent  out- 
let, when  column  H  is  not  sufficient  to  overcome  resistance  of  drip  line  and 
the  pressure  Pb  in  the  boiler.  This  air  pressure  will  continue  to  build  up 
with  vent  closed,  until  the  built-up  pressure  with  the  assistance  of  column 
H  overcomes  the  resistance  of  the  boiler  pressure.  Then  column  H  will 
fall,  the  air  vent  will  open  and  allow  escape  of  some  air,  thereby  relieving 
part  of  pressure  in  the  vent  trap.  Column  H  will  again  rise,  closing  the 
air  vent,  and  this  cycle  will  be  repeated .  When  intermittent  venting  is  repeated 
for  a  sufficient  length  of  time  under  excess  pressure  without  admitting  raw 
feed  water  containing  gases,  all  the  air  will  be  expelled  from  the  radiation. 

Such  a  system  will  continue  indefinitely  to  circulate,  due  to  a  pressure 
difference  which  will  be  fully  equal  to  that  of  its  normal  H ;  that  is,  the  pres- 
sure in  the  vent  trap  will  be  less  than  the  pressure  in  the  boiler,  by  an  amount 
equal  to  an  hydraulic  column  of  height  H  less  the  resistance  of  the  check 
valve  on  the  drip  of  this  column. 

In  modulation  systems  designed  for  a  stated  pressure  Pb  and  open  vent 
at  head  H,  the  only  difficulty  occurs  where  a  pressure  exceeding  Pb  is  built 
up  rapidly  before  the  initial  air  has  been  fully  expelled.  Under  such  con- 
ditions complete  circulation  will  not  be  obtained  as  rapidly  as  if  steam  had 
been  generated  at  a  slower  rate. 

To  overcome  the  difficulty  in  expelling  air  and  returning  condensation 
to  the  boilers,  where  excessive  pressure  is  rapidly  generated,  as  in  the  use 
of  certain  grades  of  bituminous  coal,  wood,  etc.,  a  special  high-duty  vent 
trap  should  be  employed.  In  this  trap,  due  to  the  rise  in  column  H,  the 
air  vent  is  automatically  closed  and  an  equalizing  pipe  between  the  boiler 
and  the  vent  trap  is  opened,  the  water  under  equalized  pressure  flowing 
by  gravity  to  the  boiler,  after  which  the  equalizing  pipe  is  closed  and  the 
air  vent  again  opened.  The  two  operations  taking  place  alternately,  serve 
to  vent  the  system  completely  of  air  and  also  return  the  condensation  to 
the  boiler,  regardless  of  the  boiler  pressure. 

As  follows  in  the  discussion  of  pressure  drop  in  vacuum  systems,  the 
return  mains  should  be  proportioned  relatively  to  the  steam  mains  selected 
for  equal  duty.  This  principle  applies  also  to  modulation  systems. 

The  basic  proportional  sizes  of  returns  to  supply  mains  recommended 
are  given  in  Table  11-4. 

Pressure  Drop  in  Vacuum  Systems:  The  reason  for  employing  a  vacuum 
system  rather  than  a  modulation  system  lies  in  the  greater  total  drop 
obtainable  from  a  given  initial  pressure  P  above,  to  terminal  pressure  p 
below  atmospheric,  thereby  obtaining  circulation  through  greater  resistance 
due  to  long  pipe  runs  and  lack  of  grade  for  gravity  flow  of  condensation. 

120 


Table  11-4.    Relative  Proportions  of  Steam  Supply  and  Return  Mains  in 

Modulation  Systems 


Supply  main 

Dry  return  main 

Return  riser 

Wet  return 

1 

X 

y 

K 

1  J4 

1 

Vl 

i 

1  i  ._.  mid  L' 

1U 

1 

1M 
1H 

3  and  3>i 

11^ 

1H 

1H 

1 

2 

1  !^ 

\14  and  3 

2}^ 

2 

1}^ 

6 

3 

'  2J^ 

2 

7  and  It 

3  and  3J-6 

3 

2 

9  and  10 

4  and  4J/£ 

3V£ 

2 

12 

5 

4 

2H 

Lowering  the  terminal  pressure  p  by  mechanical  exhaustion  in  return 
mains  (the  vacuum  system)  allows  greater  pressure  drops  through  each  of 
the  series  of  resistance. 

In  good  vacuum  system  practice,  the  total  drop  between  source  of  sup- 
ply through  the  inlet  valve  of  the  farthest  radiator  on  the  system  should  be 
that  between  available  initial  and  atmospheric  pressure,  so  that  normally 
the  pressure  in  the  radiator  will  be  at  or  very  slightly  below  that  of  the  at- 
mosphere. The  pressure  drop  p4  of  the  return  trap  may  usually  be  two  to 
three  times  that  permissible  in  a  well  designed  modulation  system.  The 
drop  p3  in  the  vacuum  return  lines,  if  graded  in  direction  of  flow,  may  equal 
that  in  the  supply  mains  of  the  system  under  consideration,  and  if  it  be  neces- 
sary to  elevate  the  condensation  at  one  or  more  vertical  lifts  in  order  to  ob- 
tain horizontal  grade  toward  the  vacuum  pump,  this  (within  limits  of  tem- 
perature of  condensation)  may  be  obtained  by  increasing  the  displacement 
of  air  and  vapor  by  the  pump.  In  systems  where  the  high  vacuum  neces- 
sary to  lift  the  condensation  at  one  or  more  points,  would  occasion  a  need- 
lessly high  vacuum  in  that  portion  of  return  system  which  has  a  gravity 
flow,  the  degree  of  vacuum  may  be  reduced  by  means  of  special  vacuum 
controlling  apparatus  which  provides  for  continuous  discharge  of  condensa- 
tion and  also  for  a  reduction  of  degree  of  vacuum  between  the  inlet  and 
outlet  of  the  apparatus.  (See  Chapter  15,  page  176,  for  description  of  such 
apparatus.) 

In  general,  owing  to  greater  pressure  drop,  a  vacuum  system  will  not 
require  as  large  hiains,  branches  to,  and  inlet  valves  of  radiation  as  needed 
for  a  modulation  system.  Likewise,  the  radiator  traps  and  return  mains 
may  be  smaller  for  similar  sized  units  of  radiation  provided  radiator  traps  of 
high  efliciency  are  properly  installed  to  prevent  leakage  of  steam  to  return  lines. 

Return  traps  on  radiators  should  be  proportioned  for  a  pressure  dif- 
ference of  between  Yl  and  1  lb.  depending  upon  the  condition  of  the  partic- 
ular problem. 

Return  mains  should  be  proportioned  relatively  to  the  steam  mains 
selected  for  equal  duty  by  the  table  of  comparative  sizes  (Table  11-5), 
allowing  additional  areas,  however,  where  there  is  probability  of  high  tem- 
perature in  the  outlet  end  of  returns,  due  to  steam  leakage  of  return  traps 

121 


or  lack  of  vapor  condensation  occasioned  by  thoroughly  insulated  mains 
retaining  the  heat  in  the  water  passing  through  the  radiator  traps. 

Where  high  vacuum  for  lifts  increases  the  volume  of  vapors  and  gases 
to  be  removed,  at  least  one  size  larger  return  mains  should  be  used. 

Such  degree  of  partial  vacuum  should  be  carried  by  properly  propor- 
tioned pump  displacement  as  to  cause  a  partial  vacuum  equal  to  the  selected 
pressure  difference  (p4)  through  the  most  remote  return  traps  on  the  system. 
In  proportioning  pump  displacement  for  vacuum  systems,  the  most  complex 
problem  is  that  of  proper  allowance  for  the  amount  of  vapor  and  air.  Pres- 
sure below  atmosphere  in  any  part  of  the  system  is  liable  to  induce  invisible 
air  leaks.  For  full  efficiency  of  radiation,  the  temperature  of  condensation 
passing  through  return  traps  must  be  close  to  that  due  to  the  steam  pressure 
in  the  radiator. 

Part  of  the  hot  water,  when  flowing  into  lower  pressure  in  the  return 
line,  flashes  into  vapor  of  high  specific  volume.  The  amount  may  be  deter- 
mined by  inspection  of  the  re-evaporation  chart  shown  on  page  157. 

Some  of  this  vapor  will  be  condensed  on  the  way  to  the  vacuum  pump, 
the  volume  depending  upon  whether  or  not  the  returns  are  insulated  and 
also  upon  the  amount  of  radiation,  due  to  the  length  of  the  return  pipe. 
It  must  be  borne  in  mind  that  the  vacuum  or  degree  of  partial  pressure  in 
the  return  line  cannot  exceed  that  corresponding  to  the  temperature  of  the 
water  of  condensation. 

Inleakage  of  air  through  even  minute  imperfections  in  piping  causes  an 
increase  of  volume  to  be  handled  proportionately  as  the  absolute  tempera- 
ture of  the  air  at  inleak  is  to  the  absolute  temperature  in  the  return  system, 
plus  expansion  from  that  volume  at  atmospheric  pressure  to  that  of  vacuum 
pressure. 

As  explained  in  Chapter  13  on  Vacuum  Pumps,  it  is  frequently  possible 
to  take  advantage  of  some  condensing  medium  such  as  cool  air  for  ventila- 
tion, or  water  which  must  be  warmed  for  cooking  and  washing,  boiler  feed, 
etc.,  and  use  this  medium  for  cooling  and  condensing  the  air  and  vapor 
to  decrease  its  volume  on  the  way  to  the  pump. 

Table  11-5.    Normal  Relation  of  Return  Mains  and  Risers  to  Supply  Mains 
Caring  for  Equal  Amounts  of  Steam  in  Vacuum  Systems 


Horizontal 
supply  main 

Horizontal 
return 

Vertical 
return 

Gravity  drip  vertical  outlet  at  heel  of  risers  2!/£-in.  and  under,  less 
than  12  stories  high,  %-in.  Over  12  stories  or  over  2^-in.  riser  1-in. 

lJ4-in.  and  less 

%-in. 

%-in. 

vertical  outlet  increasing  in 

horizontal  run  to  IJ^-in. 

!]/£  and  2-in. 

1 

M 

Horizontal  gravity  drips 

Number  of  ?<tor  1-in.  outlets  which 

2J^-m. 

IX 

1 

graded  at  least  }/i-m.  in 

may  be  carried  on  one  horizontal 

3  and  3J^  in. 

l\i 

1J4 

10  feel  are  usually  capa- 

run when  graded  J4-in.  in  10  feet, 

4,  4J^  and  5-in. 

2 

1J^ 

ble  of  caring  for  the  num- 

provided radiation  on  steam  riser 

6  and  7-in. 

23^ 

2 

ber  of  %  or  1-in.  outlets 

does   not   drain    as   in    one  -  pipe 

8  and  9-in. 
10-in. 

3 

2H 

as  follows: 

system 

12-in. 

4  2 

3J^ 

Size 

No.  of  3j-in.                No.  of  1-in. 

14  and  15-in. 

4V£ 

4 

horizontal 

outlets                           outlets 

16  and  17-in. 

5 

\Yi 

I'-i-in. 

12                             6 

18  and  20  in. 

6 

5 

Ijl 

18                           12 

30  18 

60  36 

100  50 


3000" 


5000" 


2'/2 


100       8" 


3'/2 


4'/2 


J0U_ 


IU 


9-. 


200 


SIZING  OF  PIPING:  The  use 
of  the  tables  in  sizing  piping  may 
best  be  explained  by  the  following 
examples. 

Vacuum  System:  Assume  a 
central  steam  generating  plant  for 
a  group  of  buildings.  Figure  11-3. 

In  the  problem  here  presented 
are  a  boiler  house  and  three  de- 
tached buildings  A,  B    and  C, 
connected  by  a  system  of  well- 
covered  mains   in  a    tunnel. 
Through  these  mains  it  is  desired  to  con- 
vey 6000  Ib.  of  steam  to  building  A,  5000 
Ib.  to  building  B,  and  3000  Ib.  to  building 
C,  per  hour,  with  a  pressure  drop  from 
16-lb.  absolute  in  the  boilers  to  or  near 
atmospheric  pressure  just  beyond  the  main 
valve  in  each  building. 

Good  covering,  still  air  at  about  70 
deg.  and  proper  drainage  are  assumed. 

The  total  steam  requirement  per  hour 
of  buildings  A,  B  and  C  is  14,000  Ib. 

The  longest  run  of  main  is  from  the 
boiler  house  to  building  C  and  without 
allowance  for  fittings  is  880  ft. 

In  estimating  the  sizes  of  pipes  by  the 
use  of  Table  11-2  it  is  necessary  to  first 
find  the  drop  of  pressure  per  1000  ft. 
and  then  to  find  the  corresponding  quan- 
tity of  steam  flowing  through  the  pipe 
for  a  drop  in  pressure  of  1  Ib.  for  this  dis- 
tance of  1000  ft. 

The  pressure  drop  varies  directly  as  the  length  of  a  pipe,  and  the  weight 
of  steam  discharged  through  a  pipe  varies  directly  as  the  square  root  of  the 
pressure  drop.    We  therefore  multiply  a  given  weight  of  steam  by 
!  1  Ib.  x  (the  tabular  pressure  drop  per  1000  ft.) 

^         The  given  pressure  drop  per  1000  ft. 
to  find  the  equivalent  weight  of  steam  at  1-lb.  drop  per  1000  ft. 

The  assumed  drop  in  pressure  is  16  --  14.7  =  1.3  Ib.  per  sq.  in. 
For  a  given  total  drop  of  1.3  Ib.,  the  drop  per  1000  ft.  is 

x  1000  -  1.4811). 


14 


20 

£»5 

20' 


Fig.  H-3.  Illustrat- 
ing the  problem  of  siz- 
ing steam  and  return 
lines  for  group  of  build- 
ings us  described  in  the 
text 


\J\J\' 

The  first  section  of  pipe  to  A  conveys  14,000  Ib.  per  hr.  and  the  cor- 
responding weight  of  steam  at  1-lb.  drop  per  1000  ft.  is 


118"  x 


123 


Referring  to  Table  11-2  we  find  that  to  convey  11500  Ib.  per  hr.  at  a 
pressure  drop  of  1  Ib.  per  1000  ft.  requires  a  12-in.  pipe. 

The  second  section  of  main  from  A  to  B  conveys  8000  Ib.  per  hr.  at 
a  pressure  drop  of  1.48  Ib.  per  1000  ft.  Using  the  same  reasoning  we  find 
that  the  corresponding  weight  of  steam  at  1-lb.  drop  per  1000  ft.  is 

J_  x  8000  =  6600  Ib. 
V  1.48 

From  Table  11-2  the  pipe  size  is  found  to  be  10-in. 
Similarly  the  branch  from  B  to  building  C  conveys  3000  Ib.  per  hour 
at  1.48  Ib.  drop  per  1000  ft. 

The  corresponding  weight  at  1  Ib.  drop  per  1000  ft.  is 

l~f~ 

_L  x  3000  =  2460  Ib. 
1.48 

And  from  Table  11-2  the  pipe  size  is  7-in. 

The  total  steam  to  be  carried  will,  however,  be  in  excess  of  14000  Ib. 
by  the  amount  condensed  in  the  mains. 

The  pressure  drop  for  pipe  friction  will  be  less  than  1.3  Ib.  by  the  amount 
necessary  for  initial  velocity. 

The  length  of  run  equivalent  to  the  lineal  run  plus  the  added  allowances 
for  fittings  as  shown  in  Table  11-3  will  be  materially  in  excess  of  880  ft. 

It  is  therefore  evident  from  an  inspection  of  the  plan  that  the  above 
trial  sizes  may  be  too  small  and  that  it  will  be  advisable  to  assume  an  increase 
of  one  size  of  pipe  above  those  previously  assumed,  in  all  cases  where  there 
is  a  considerable  number  of  fittings  etc.  This  is  true,  in  this  problem,  in 
the  first  section  of  the  main. 

The  trial  sizes  will  then  be,  14-in.  for  the  run  to  branch  A;  10-in.  to 
branch  B  and  7-in.  to  C. 

Condensation  Allowances:  For  425  ft.  of  14-in.  main  from  the  boiler 
to  branch  A. 

From  Table  11-2  we  find  the  square  feet  of  surface  per  lineal  foot  of 
pipe  to  be  3.9  sq.  ft.,  this  equals  1657.5  sq.  ft.  for  the  425  ft.  of  14-in.  main. 
To  this  should  be  added  5  per  cent  for  radiation  from  fittings  making  approxi- 
mately 1740  sq.  ft.,  radiating  50  B.t.u.  per  sq.  ft.  per  hr.,  when  the  tempera- 
ture drop  is  216  deg.  -  70  deg.  =  146  deg.  Multiplying  50  (B.t.u.)  by 
1740  (sq.  ft.)  and  dividing  by  968  gives  the  total  condensation  for  the  14-in. 
main,  which  equals  approximately  90  Ib. 

The  10-in.  main  condenses  2.82  (sq.  ft.  of  surface  per  lineal  ft.)  X  200 
(ft.)  X  50  +  968  or  29.2  Ib.  +  5  per  cent  for  fittings  =  31  Ib. 

The  7-in.  main  condenses  2  X  255  X  50  H-  968  or  26.4  Ib.  +  5  per 
cent  for  fittings  =  28  Ib. 

It  is  evident  that  the  condensation  of  the  branches  will  be  a  small 
portion  of  the  total  quantity  of  steam  carried  by  the  main  or  branches. 
Estimating  by  comparison  with  branch  to  C,  it  is  obvious  that  branches 
to  A  and  B  will  condense  hardly  more  than  40  Ib.  per  hour  each. 

This  gives  us  the  total  quantity  of  steam  to  be  carried  by  the  14-in. 
main;  14000  +  90  +  31  +  28  +  40*  +  40  =  14229  Ib.  per  hr.  ' 

124 


The  10-in.  main  carries  8000  +  31  +  28  +  40   -  8099  Ib.  per  hr. 
The  7-in.  branch  to  C  carries  3000  +  28  =  3028  Ib.  per  hr. 
Pressure  Drop  for  Initial  Velocity:     In  a  14-in.  main  conveying  18970 
Ib.  per  hour  the  velocity  is  7060  ft.  per  min.,  from  Table  11-2.    At  14229  Ib. 

14229 

per  hour  the  velocity  will  be  x  7060  =  5300  ft.  per  min. 

From  Table  11-1  we  find  that  0.0625  Ib.  is  required  to  accelerate  the 
steam  from  rest  in  the  boiler  to  a  velocity  of  5520  ft.  per  min.  in  the  main. 


For  5300  ft.  per  min.  the  drop  is  therefore  x  0.0625  Ib.  =  0.06  Ib.  drop 


velocity  head.  The  residual  pressure  available  for  overcoming  friction 
in  the  mains  and  branches  is  1.3  --  0.06  =  1.24  Ib.  per  sq.  in. 

Referring  to  Table  11-3  we  find  the  equivalent  resistance  in  feet  of 
straight  pipe  to  be  added  to  the  run  for  friction  in  fittings,  etc.  The  various 
quantities  are  tabulated  on  page  126  and  the  summation  of  the  quantities 
gives  the  equivalent  length  of  pipe  for  each  section  and  for  the  total.  We 
find  that  the  revised  equivalent  run  is  now  1559  ft.  and  with  a  given  drop  of 
1.24  Ib.  in  the  total  run,  the  drop  per  1000  ft.  is  0.796  Ib.  In  the  last  column 
s  found  the  revised  actual  pressure  drop  for  each  section. 

The  pressure  drop  through  a  pipe  varies  as  the  square  of  the  weight 
flowing  through  it.  If  we  know  the  weight  of  steam  discharged  through  a 
pipe  w  th  1-lb.  drop  per  1000  ft.  (as  from  Table  11-2)  and  wish  to  find  the 
drop  of  some  other  weight  (as  the  weights  in  column  q  on  next  page)  we  can 
obtain  it  by  applying  this  law.  The  square  of  the  quotient  of  the  given 
weight  divided  by  the  tabular  weight,  times  the  tabular  drop  equals  the 
drop  for  the  given  quantity  (column  s). 

The  total  drop  of  1.16  Ib.  shown  in  the  table  is  as  close  to  the  desired 
drop  as  can  be  expected  with  commercial  sizes  of  pipe.  If  the  deviation 
had  been  greater,  one  or  more  of  the  trial  sizes  would  have  to  be  altered 
to  bring  the  total  drop  nearer  that  desired.  Inspection  of  column  s  will 
show  in  which  portion  or  portions  of  the  main  the  drop  per  1000  ft.  is  farther- 
est  from  the  average  of  0.796  Ib. 

It  is  this  section  or  sections  that  should  be  refigured. 

The  pressure  available  for  friction  in  the  branches  is  the  difference 
between  the  total  available  drop  of  1.24  Ib.  and  the  amount  already  utilized 
in  the  main  up  to  the  junction  with  the  branch  in  question. 

The  procedure  for  determining  branch  sizes  is  exactly  the  same  as 
for  the  mains;  assuming  one  size  larger  than  the  calculated  trial  size,  adding 
condensation  and  allowance  for  fittings  and  checking  to  see  that  the  actual 
drop  to  the  building  is  close  to  the  permissible  drop. 

The  drop  in  the  branch  to  A  is  1.24  Ib.  --  0.518  Ib.  =  0.722  Ib.  Di- 
viding this  by  255  ft.  (actual  length  of  run  to  A)  X  1000  gives  2.83  Ib. 
drop  per  1000  ft.  in  this  run. 

The  corresponding  weight  at  1-lb.  drop  per  1000  ft.  is: 


, 


X  600°  (lb')  =356°  lb>;  re<luirmg  (from  Table  11-2)  8-in.  pipe. 


The  drop  in  the  branch  to  B  is  1.24  Ib.  -  0.768  Ib.  =  0. 172  Ib.  Dividing 

125 


Table  11-6 


From 
Table  11-2 
Weight 

Actual 
pressure 
drop  per 

Actual 
drop  in 
section 

Equivalent 

'Total 

passed  by 

1000  ft. 

of  main 

Trial 
size 

Actual 

length 
for 

equivalent 
length 

Weight 
of 

trial  size  at 
1-lb.  drop 

fiV,, 

(lb.)  -—  „  s 

Section 

pipe 

length 

fittings 

(n+o) 

steam 

per  1000  ft. 

\  r  / 

1000 

m 

n 

o 

p 

q 

r 

s 

t 

Boiler  house 

14-in. 

125 

1  Gl.  V. 

903ft. 

14229 

18970 

,56t  Ib. 

.518  Ib. 

to  branch  A 

160  ft. 

Ib. 

per  hr. 

Ib.  per  hr. 

6  ells 

318  ft. 

478  ft. 


Branch  A 

run  of 

to 

reducing 

22  1  ft. 

branch  B 

10-in.            200                 tee 

24  ft. 

8099  Ib.   7680  Ib.   1.12  Ib.    .25  Ib 
per  hr.    per  hr. 


Tot.  24  ft. 


Branch  B 

1  Gl.  V.  82ft. 

to 

7-in.              255       3  ells  78  ft.     432ft. 

3028  Ib. 

3155  Ib.      .921  Ib. 

.398  Ib. 

bldg.  C 

run  of 

per  hr. 

per  hr. 

reducing 

tee   17   ft. 

Tot,  177  ft. 


Total  equiv.  main  1559  ft. 


Total  drop    1.166  Ib. 


this  by  155  times  1000  gives  3.04-lb.  drop  per  1000  ft.  in  this  run.     The 
corresponding  weight  is 


1 


^|  O  . 


x  5000  (Ib.)  =  2880  Ib.  requiring  a  7-in.  pipe. 


Assume  for  the  first  trial,  one  size  larger  than  figured  above,  to  take  care 
of  the  comparatively  large  number  of  fittings,  etc.  The  branch  to  A  will 
be  9-in.  and  to  B,  8-in. 

The  estimated  quantities  of  condensation  are  close  enough  for  use  in 
sizing  these  branches.  The  total  quantity  carried  by  branch  to  A  is  there- 
fore 6000  +  40  =  6040  Ib.  and  by  branch  to  B,  3000  +  40  =3040  Ib. 

Table  11-7 


Weight 

Actual 
pressure 

passed 

dro] 

> 

Drop 

Total 

by  trial 

per  10 

DO  ft. 

Actual 

in 

drop 

Section 

Trial 
size 
pipe 

Total 
equivalent 
Fittings              length 

Weight 
of 
steam 

size  with 
1-lb.  drop 
per  1000  ft. 

(f)'> 

r  1  (Ib. 

drop 
)       in 
branch 

mam 
to 
branch 

boiler 
house 
to  bldgs. 

u 

v 

w 

X 

y 

z 

wXz 

Branch 

9-in. 

br.  tee  68  ft 

.  2  ells 

497  ft. 

6040 

tb.  5900  Ib. 

1.04 

Ib. 

.52  Ib. 

.518  Ib 

1.038  Ib. 

A 

70  ft.  Gl.  V. 

104  ft. 

Total  242  ft. 


Branch  8-in.    br.  tee  63  ft.  2  ells  374  ft. 

B  62  ft.  Gl.  V.  94  ft. 

Total  219  ft. 


5040  Ib.   4400  Ib.    1.31  Ib.    .49  Ib.     .768  Ib.   1.258  Ib. 


126 


Since  the  total  drop  from  the  boilerhouse  to  the  building  in  each  case 
is  not  tnr  from  1.21  lb.,  or  is  at  least  as  close  as  commercial  sizes  of  pipe 
will  allow,  the  trial  sizes  of  9-in.  to  A  and  8-in.  to  B  are  correct. 

The  sizes  of  return  mains  should  be  based  upon  the  sizes  of  the  corre- 
sponding steam  mains  in  the  foregoing  example. 

By  referring  to  Table  11-5  we  find  as  follows:  branch  returns  from 
buildings  B  and  C  are  respectively  3-in.  and  2^-in.  to  the  junction,  where 
they  increase  to  SJ/^-in.,  continuing  this  size  to  the  point  where  the  3-in. 
return  from  building  A  joins  the  above.  Increase  the  return  here  to  4J^-in. 
and  continue  this  size  to  the  vacuum  pump  in  the  boiler  house. 

Long  computations  such  as  the  above  are  required  only  in  connection 
with  extensive  distributing  systems,  where  the  cost  of  one  size  larger  pipe 
becomes  important. 

For  general  use  in  sizing  mains,  branches  and  risers  for  both  modulation 
and  vacuum  systems,  Tables  11-8  A,  B,  C  and  D  will  be  found  sufficiently 
accurate  if  used  with  discretion.  They  are  based  upon  75  per  cent  of  the 
values  of  Table  11-2  and  will  cover  an  ordinary  amount  of  valves,  fittings, 
etc.,  if  globe  valves  are  excluded. 

In  the  use  of  Tables  11-8  A,  B,  C  and  D  the  permissible  pressure  drop 
between  the  inlet  of  the  supply  main  and  the  farthest  radiator  determines 
the  alphabetical  sub-division  of  the  table  which  is  to  be  used.  Table  23-7 
in  Chapter  23  gives  a  list  of  pressure  differentials,  which  will  be  found  reason- 
ably accurate  for  various  types  of  modulation  and  vacuum  systems  under 
ordinary  conditions. 

The  following  rules  should  be  employed  to  determine  which  column 
of  length  of  run  should  be  used  for  horizontal  or  vertical  pipes  in  the  alpha- 
betical sub-division  selected. 

1.  For  horizontal  supply  pipes,  find  the  total  run  in  feet  along  the  pipe 
from  the  source  to  the  farthest  radiator  and  use  the  corresponding  column 
in  the  table. 

2.  For  sizing  up-feed  risers,  add  ,Hff  of  the  length  of  the  vertical  pipes 
to  the  total  run  found  by  Rule  1,  and  use  corresponding  column  in  table. 

3.  For  sizing  down-feed  risers  deduct  ,"V  of  the  length  of  the  vertical 
pipes  from  the  total  run  found  by  Rule  1,  and  use  the  corresponding  column 
in  the  table. 

4.  The  sizing  of  supply  run-outs,  especially  those  in  which  the  con- 
densation must  flow  by  gravity  in  the  opposite  direction  to  the  steam  current, 
calls  for  special  consideration  and  will  be  discussed  in  Chapter  12  on  Critical 
Velocities  in  Radiator  Run-outs. 

5.  The  sizes  of  return  mains  and  run-outs  should  be  based  on  the  sizes 
of  supply  mains,  which  will  take  care  of  a  similar  quantity,  and  are  found 
by  reference  to  Table  11-5.     For  convenience,  the  correct  sizes  of  return 
mains  and  risers,  for  a  given  number  of  pounds  of  condensation,  length  of 
run  and  pressure  differential,  are  also  contained  in  Table  11-8  A,  B,  C  and  D. 

Modulation  System:  In  sizing  piping  for  modulation  systems,  long  com- 
putations such  as  described  under  vacuum  systems  are  not  necessary. 
The  Tables  11-8  A  to  8  D  are  sufficiently  accurate  for  ordinary  conditions. 

127 


Table  11-8.    Ratings  of  Supply  and  Return  Mains  in  Pounds  of  Steam  per  Hour, 

for  Various  Pressure  Drops  from  Initial  Pressure  of  16  Ib.  Absolute, 

when  in  Horizontal  Runs  of  from  300  to  1,000  ft. 

These  tables  are  found  by  taking  75  per  cent  of  the  values  of  straight  pipe  given  in  Table  11-2,  to 
cover  an  ordinary  number  of  valves  and  fittings,  entrance  velocity  and  other  resistances  to  the  flow  of  steam 

A — %-lb.  Drop  in  Pressure 


Pipe  sizes  for  modulation  systems 

Length  of  run  in  feet 

Return  (from  table  114) 

Steam  supply 

300 

400                          500 

750 

1,000 

Return 
riser 

Dry  return  main 

Rating  in  pounds  of  steam  per  hour 

%" 

X" 

1" 

7.08 

6.12                 5.48 

4.48 

3.88 

3A" 

1" 

IK" 

16.9 

14.6                 13.1 

10.7 

9.25 

l" 

IK" 

ilA" 

26.6 

23 

20.6 

16.85 

14.6 

l" 

IX" 

2" 

55.4 

47 

8                 429 

35. 

30.35 

IK" 

iw 

21A" 

91.5 

79.                    71. 

57.8 

50.2 

W 

iy2" 

3" 

169. 

146.                  131. 

107. 

92.5 

IJi" 

llA" 

3H" 

249.5 

215 

5               193.4 

157.7 

136.5 

1H" 

2" 

4" 

353.5 

305.                 274. 

223.5 

193.6 

9" 

2y2" 

5" 

642.5 

554 

498. 

406. 

352. 

21A" 

3" 

6" 

1043. 

900 

808. 

660. 

'    572. 

3" 

3" 

7" 

1525. 

1318 

1185. 

965. 

836. 

3" 

31A" 

8" 

2130. 

1840 

1650. 

1347. 

1168. 

3H" 

4" 

9" 

2855. 

2465 

2215. 

1806. 

1564. 

31A" 

W 

10" 

3835. 

3315 

2975. 

2425. 

2110. 

4" 

5"     • 

12" 

6060. 

5230 

4700. 

3835. 

3320. 

5" 

6" 

14" 

9175. 

7920 

7120. 

5800. 

5030. 

5" 

6" 

16" 

11320. 

9780 

8780. 

7160. 

6210. 

9" 

7" 

]8" 

15350. 

13280. 

11900. 

9720. 

8410. 

7" 

8" 

20" 

20100. 

17400. 

15600. 

12720. 

11030. 

B  — 


Drop  in  Pressure 


Pipe  sizes  for  modulation  systems 


Length  of  run  in  feet 


Return  (from  table  11-4) 

Steam  supply 

300' 

400' 

500' 

750' 

1,000' 

Return 
riser 

Dry  return  riser 

Rating  in  pounds  of  steam  per  hour 

K" 

1" 

10.03 

8.67 

7.75 

6.34 

5.48 

3/" 

1" 

23.9 

20.7 

18.5 

15.1 

13.1 

I"* 

IK" 

1  12» 

37.7 

32.6 

29.2 

23.8 

20.6 

1" 

2" 

78.4 

67.8 

60.7 

49.6 

42.9 

IK" 

\M" 

2^3" 

129.5 

112. 

100.3 

81.8 

71. 

In" 

3" 

239. 

207. 

185. 

151.2 

131. 

\y" 

iy 

353. 

305.5 

273. 

223. 

193.4 

ij|" 

2" 

4"2 

510. 

433. 

387. 

316. 

274. 

2" 

2Y" 

5" 

910. 

786. 

704. 

574. 

498. 

3" 

6" 

1478. 

1280. 

1142. 

933. 

808. 

3" 

3" 

7" 

2160. 

1870. 

1670. 

1365. 

1185. 

3" 

8" 

3015. 

2610. 

2335. 

1905. 

1650. 

sy 

4" 

9" 

4040. 

3495. 

3125. 

2550. 

2215. 

31/" 

10" 

5430. 

4700. 

4200. 

3130. 

2975. 

4" 

5"2 

12" 

8580. 

7420. 

6640. 

5430. 

4700. 

5" 

6" 

14" 

13000. 

11250. 

10060. 

8220. 

7120. 

5" 

6" 

16" 

16050. 

13890. 

12400. 

10130. 

8780. 

6" 

7" 

18" 

21750. 

18820. 

16820. 

13750. 

11900. 

7" 

8" 

20" 

28500. 

21650. 

22050. 

18000. 

15600. 

128 


Table  11-8 — Continued 

C — l/2-lb.  drop  in  pressure 


Pipe  sizes  for   modulation  systems 

Length  of  ren  in  feet 

Pipe  sizes  for  vacuum  svstems 

Return    from  table 
11-4) 

Steam 
supply 

300'               400'           SCO'            750'           1000' 

Steam 
supply 

Return  (from  table 

11-5) 

Return 
riser 

Dry  ret. 

main 

Ratings  in  pounds  of  steam  per  hour 

Horiz. 

Vert. 

H" 

H" 

1" 

14.18        12.28      10.98      8.95      7.75 

1" 

K" 

w 

3A" 

l" 

IK" 

33.8        29.25      26.2      21.35    18.5 

IK" 

8" 

H" 

I" 

VA" 

1H" 

53.3        46.2        41.3      33.7      29.2 

IK- 

i" 

K" 

i" 

IK" 

2" 

110.8        96.           85.8      70  3      60.7 

2" 

i" 

%" 

W 

IK" 

2K" 

183.         158.6      142.       115.8     100.-3 

2K" 

IK" 

i" 

IK" 

IK" 

3" 

338.         292.5      262.       213.5     185. 

3" 

iS" 

w 

Ijl" 

1>|" 

3K" 

498.         432.         386.5    315.       273. 

3K" 

IH" 

V/4" 

IK" 

2" 

4" 

707.         612.         548.       447.       387. 

4" 

2" 

l%" 

0" 

2K" 

5" 

1285.       1113.         997.       813.       704. 

5" 

2" 

VA" 

2K" 

3" 

6" 

2085        1808.       1620.     1320.     1142. 

6" 

2K" 

2" 

3" 

3" 

7" 

3050.       2645.       2365.     1930.     1670. 

7 

2K" 

2" 

3" 

3K" 

8" 

4260.       3690.       3300.     2695.     2335. 

8" 

3" 

W 

3K" 

4" 

9" 

5720.       4945.       4430.     3610.     3125. 

9" 

3" 

21A" 

3K" 

4K" 

10" 

7675.       6650.       5950.     4850.     4200. 

10" 

3K" 

3" 

4" 

5" 

12" 

12130.     10500.       9400.     7660.     6640. 

12" 

4" 

"3^" 

5" 

6" 

14" 

18360.     15900.     14220.    11600.    10060 

14" 

4K" 

4" 

5" 

6" 

16" 

22620.     19610.     17560.    14310.   12400. 

16" 

5" 

4^" 

6" 

7" 

18" 

30750.     26600-.     23800.    19420.    16820 

18" 

6" 

7" 

8" 

20" 

40250.     34850      31200.   25420.   22050 

20" 

6" 

5" 

D — 1-lb.  drop  in  pressure 


Pipe  sizes  for  modulation  systems 

Length  of  run  in  feet 

Pipe  sizes  for  vacuum  systems 

Return  (from  table 
11-4) 

Steam 
supply 

300'             400'           500"           750'             \OOff 

Steam 
supply 

Return  (from  taDle 
11-5) 

Return 
riser 

Dry  ret. 
main 

Ratings  in  pounds  of  steam  per  hour 

Horiz. 

Vert. 

1A" 

*A" 

1" 

20.2      17.4        15.5      12.65       10.98 

1" 

%" 

»/" 

H" 

1" 

IK" 

47.8      41.4        37.         30.2        26.2 

S/" 

3/" 

I" 

IJi" 

IK" 

75.4      65.4        58.3      47.6        41  3 

IK" 

1" 

S/" 

i" 

IK" 

2" 

157.       136.         121.5      99.           85.8 

2" 

1" 

8" 

1/4" 

IK" 

2K" 

259.       225.         202.       163.6      142. 

2K" 

iy 

i" 

IK" 

IK" 

3" 

478.       414.         370        302.         262 

3" 

IK" 

IK" 

IK" 

3K" 

706.       612.         546.       446.         386.5 

3K" 

IK" 

i1/" 

IK" 

2" 

4" 

1000.       867.         774.       632.         548. 

4" 

2" 

IK" 

2" 

2K" 

5" 

1820.     1575.       1410.     1150.         997 

5" 

2" 

IK" 

2K" 

3" 

6" 

2955.     2565.       2282.     1867.       1620 

6" 

2K" 

2" 

3" 

3" 

7" 

4320.     3750.       3340.     2730.       2365 

7" 

2K" 

2" 

3" 

3K" 

8" 

6030.     5230.       4660.     3810.       3300. 

8" 

**  /  & 

3" 

2K" 

3K" 

4" 

9" 

8080.     7020.       6250      5110        4430 

9" 

3" 

9I/" 

3K" 

4K" 

10" 

10870.     9425        8400      6860.       5950 

10" 

3K" 

3"2 

4" 

5" 

12', 

17160.   14900      13300     10850        9400 

12" 

4" 

5" 

6" 

14" 

26000.   22550.     20130.   16400.     14220. 

14" 

4K" 

4" 

5" 

6" 

16" 

32050.   27810.     24800.   20250       17560 

16" 

5" 

4K" 

6" 

7" 

18" 

13500.   37720.     33620.   27450.     23800 

18" 

6" 

5" 

7" 

8" 

20" 

57000.   49400.     44100.   36000.     31200 

20". 

6" 

5" 

The  total  quantity  of  steam  to  be  supplied  per  hour  at  the  time  of  maxi- 
mum normal  heating  effect  being  a  known  factor  and  the  total  maximum 
pressure  drop  in  the  heating  system  being  determined  for  this  period,  the 
pressure  drop  in  the  supply  main  must  be  so  chosen  that  the  pressure  to  be 
carried  on  the  boiler  will  exceed  by  a  safe  margin  the  sum  total  of  resistances 
between  the  boiler  and  the  outlet  of  the  vent  valve. 

For  an  illustration,  assume  a  typical  modulation  system  which  requires 
500  Ib.  of  steam  per  hour  for  maximum  normal  heating  effect.  The  length 
of  run  is  assumed  to  be  300  ft.  and  the  boiler  pressure  is  not  to  exceed 
i/£-lb.  gauge. 

To  find  the  proper  size  of  supply  main  to  meet  these  conditions,  the 
pressure  drops  from  p  to  pe  as  described  in  the  discussion  of  pressure  drop 
in  modulation  systems,  Page  116,  must  be  determined,  before  the  permis- 
sible pressure  drop  p7  in  the  supply  main  can  be  ascertained. 

During  maximum  normal  heating  effect  we  find  the  pressure  drop  from 
p  to  p 6  to  be  as  follows: 

p    =  constant  at  atmospheric  pressure  = 0.000-lb.  gauge 

P!  =  pressure  drop  through  vent  check  valve  (intermittent 

at  that  period)  =  1/20  Ib.  = 0.050  " 

p2  =  pressure  drop  through  vent  valve  orifice  (negligible  at 

that  time)  = . 0.000  " 

p3  =  pressure  drop  in  return  main.     Negligible  if  return  has 

proper  grade  = 0.000  " 

p4  =  pressure  drop  through  orifice  of  radiator  trap,  which  for 
the  given  condition  will  be  the  maximum  tabular  value 

of  y8  lb.= 0.125  " 

p5  =  pressure  drop  through  radiator.      Negligible  at  that 

time  = .0.000  " 

p6  =  pressure  drop  through  radiator  valve  will  be  the  maxi- 
mum  tabular   value    for   the   given  period,   Y%  Ib.  =0.125 

Total  drop  p  to  p6  = 0.300 

The  pressure  to  be  carried  on  the  boiler    =  }^  Ib 0.500 

Pressure  drop  p  to  pe  = 0.300 

Difference  of  pressure  available 0.200 

Bearing  in  mind  that  in  addition  to  the  pressure  drop  p7  in  the  supply 
main,  we  must  consider  also  the  pressure  drop  ps  to  impart  initial  velocity, 
we  readily  see  that  a  pressure  drop  of  %  Ib.  in  the  supply  main  would  be 
unsafe  and  we,  therefore,  select  the  Y%-Vo.  drop  in  the  supply  main  p7  as  the 
basis  for  determining  the  size  of  pipe  required. 

We  find  by  referring  to  Table  11-8  A  that  a  5-in.  main  is  necessary  to  sup- 
ply 500  Ib.  of  steam  with  Vg-lb.  drop  in  pressure  in  a  run  of  300  ft. 

We  now  have  to  determine  the  head  or  pressure  drop  p8  necessary  to 
impart  initial  velocity  to  the  steam. 

From  Table  11-2,  we  find  S,  the  cubic  ft.  per  pound  of  steam  at  15.3 
Ib.  absolute  (assumed  boiler  pressure)  is  very  nearly  26.27. 

Converting  the  total  steam  required  in  pounds  per  hour  into  cubic 
feet  per  minute 

130 


500  X  26.27       13135  ,t 

6Q         =  — gg-  =  218.9,  or,  say,  219  cu.  ft. 

By  referring  to  Table  11-2,  column  3,  we  find  the  linear  feet  per  cubic 
foot  volume,  which  for  a  5-in.  pipe  is  7.22. 

Multiplying  219  by  7.22  we  obtain  the  velocity  in  feet  per  minute  of 
the  steam  to  be 1582  ft. 

We  now  determine  the  pressure  drop  ps  necessary  to  impart  initial 
velocity  and  by  referring  to  Table  11-1  we  find  for  a  2500-ft.  velocity,  a  pres- 
sure drop  of  0.01  lb.,  which  for  a  1582-ft.  velocity  would  be  approximately 
0.009  lb.  per  sq.  inch. 

The  total  pressure  drop  between  the  boiler  and  the  outlet  of  the  vent 
valve  then  becomes: 

Pressure  drop  p  -  p6  as  stated  before  = 0.300-lb.  gauge 

Pressure  drop  p7  in  main  Y%  lb.  = 0.125  ' 

Pressure  drop  ps  to  impart  initial  velocity  = 0.009  "       " 

Total  pressure  drop   =   0.434-lb.  gauge 

We  find  an  effective  differential  in  pressure  between  the  boiler  pressure 
and  the  pressure  losses  in  the  sytemof  0.500  —0.434  =  0.066  lb.  gauge,  for 
maintaining  circulation  in  the  system  during  the  period  of  maximum 
heating  effect. 

This  proves  that  for  the  above  condition,  the  J/s-lb.  drop  in  pressure  in 
p7  is  the  proper  basis  for  selecting  the  table  to  be  used,  and  this  being  de- 
termined, the  intermediate  sizes  of  the  main  and  branches  are  taken  from  same. 

The  sizing  of  run-outs  requires  special  consideration  as  described  in 
detail  in  Chapter  12,  Critical  Velocities  in  Radiator  Run-outs. 

The  sizing  of  returns  involves  the  same  procedure  with  modulation 
systems  as  outlined  before  in  the  discussion  of  sizing  of  piping  for  vacuum 
systems.  The  size  of  the  return  depends  on  the  size  of  supply  for  an  equal 
duty.  By  referring  to  Table  11-4,  we  find  that  the  size  of  return  correspond- 
ing to  a  5-in.  supply  main  is  2^  in.,  which  is  the  size  we  select. 

Taking  care  of  the  condensation  in  the  steam  main  at  the  far  point  is 
often  found  necessary  in  modulation  systems  in  which  case  the  pipe  sizes 
must  be  increased  toward  the  end  of  the  run,  beyond  the  tabular  values,  to 
take  care  of  the  reduction  in  effective  area  of  the  pipe  due  to  the  condensa- 
tion being  carried  along  with  the  steam. 

A  further  reason  for  increasing  the  sizes  of  the  pipes  toward  the  end  of 
the  run  is  to  compensate  for  the  air  carried  along  with  the  steam  in  the  pipes, 
which,  if  not  properly  relieved,  will  retard  the  circulation  of  steam  to  a  great 
extent. 

Air  relief  connections  must  be  provided  at  the  ends  of  the  runs,  through 
thermostatically  actuated  return  traps  into  the  nearest  dry  return,  in  all 
cases  where  gravity  drips  are  made  into  a  wet  drip  line. 


131 


CHAPTER  XII 

Critical  Velocities  in  Radiator  Run-outs 

THE  velocity  in  a  nearly  horizontal  pipe  in  which  the  condensation  is  to 
be  drained  by  gravity  in  the  opposite  direction  to  the  flow  of  steam 
above  it,  becomes  critical,  when  it  reaches  such  rate  that  any  velocity 
increase  will  cause  the  condensation  to  be  swept  upgrade  against  gravity. 
The  need  has  been  apparent  to  heating  engineers  of  definite  information 
regarding  this  critical  velocity  of  steam  in  branch  run-outs  to  radiation  in 
which  condensation  must  be  drained  in  a  direction  opposite  to  steam  flow. 

Individual  opinion  based  on  experience  regarding  velocity  permissible 
at  given  slope  without  danger  of  noise  due  to  surging,  varies  fully  300  per  cent. 

Many  modern  buildings  have  very  limited  space  in  which  to  run  pipes 
between  the  finished  floor  and  the  main  beams  and  fireproof  construction. 
There  are  many  valid  objections  to  exposing  the  run-outs  above  the  finished 
floors,  and  the  question  frequently  arises  as  to  the  proper  size  and  grade  for 
such  pipes  in  the  available  space  beneath  the  finished  floor. 

Fundamentally  the  size  of  pipe  for  a  given  radiator  run-out  is  de- 
pendent on  the  maximum  number  of  heat  units  to  be  conveyed  in  a  given  time. 
The  latent  heat  content  per  cubic  foot  of  steam  at  the  range  of  pressures  usual 
in  modern  "low-pressure"  heating  is  least  at  the  lower  pressures.  Denser 
steam  at  higher  pressures  undoubtedly  sets  up  greater  wave-forming  friction 
of  steam  over  surface  of  the  condensation  and  will  sweep  the  water  up  the 
slope  at  a  slightly  lower  steam  velocity  than  that  at  which  the  condensation 
will  flow  against  the  current  of  less  dense  steam.  These  facts  in  a  measure 
offset  each  other  and  the  small  error  in  the  final  result  will  have  less  effect  on 
the  problem  than  the  inaccuracies  of  grade  liable  to  exist  despite  any  reason- 
able care  in  erection. 

In  an  endeavor  to  fix  the  critical  velocity,  a  carefully  conducted  series 
of  tests  has  been  made.  The  first  of  this  series  was  with  glass  tubes,  to 
determine  visually  just  what  took  place  when  steam  at  various  velocities 
passed  over  its  condensation  in  pipes  graded  against  the  steam  flow.  The 
result  of  this  series  was  very  instructive  in  determining  the  effect  of  velocity 
and  what  to  look  out  for  in  subsequent  tests.  The  second  tests  were  with 
commercial  pipe  of  1  in.,  \%  in.,  1%  in.  and  2  in.  sizes,  each  18  ft.  long; 
each  pipe  being  tested  at  uniform  grades  of  34  m->  /^  m-»  1  m-  and  IH  m- 
in  10  ft. 

It  was  found  that  the  difference  in  critical  velocity  in  the  various  sizes 
of  pipe  under  test  differed  less  at  the  same  slope  than  the  errors  incidental 
to  careful  observation.  In  consequence  of  the  fact  that  the  size  of  pipe  had 
no  direct  relation  to  critical  velocity,  only  one  size  was  tested  at  a  grade  of 
3  in.  in  10  ft.  to  complete  the  curve  of  velocity  at  slope. 

The  result  of  these  tests  upset  some  preconceived  theories  and  estab- 
lished some  facts  that  appear  to  be  fundamental.  These  established  facts  are : 

1.  That  the  size  of  the  pipe  has  no  visible  relation  to  the  critical  ve- 
locity, which  was  practically  the  same  in  all  sizes  tested. 

132 


2.  That  the  normal  volume  of  condensation  in  a  covered  pipe  as  compared 
with  an  uncovered  pipe,  had  no  effect  on  the  critical  velocity.    In  fact,  increase 
in  condensation  up  to  the  point  where  the  volume  of  water  limited  the  free 
area  for  steam  and  made  a  material  difference  in  velocity,  the  condensation 
continued  to  flow  as  with  normal  condensation. 

3.  That  greater  or  less  length  of  run  if  at  uniform  slope  makes  no  ma- 
terial difference.    The  controlling  velocity  is  that  in  the  first  foot  or  two  of 
pipe,  and  if  the  velocity  existing  there  is  above  critical,  it  will  sweep  the 
condensation  to  the  high  end.    In  fact,  increase  in  condensation  up  to  the 
point  where  the  volume  of  water  limited  the  free  area  for  steam  and  made  a 
material  difference  in  velocity,  caused  no  change  in  flow  of  condensation. 

4.  That  the  direction  of  flow  in  the  vertical  supply  riser  to  which  the 
run-out  is  connected,  will  have  a  slight  effect  on  the  critical  velocity  in  the 
run-out.    The  critical  velocity  is  lower  in  a  down-feed  than  in  an  up-feed 
riser.    This  is  due  to  the  change  in  direction  of  the  highest  velocity  steam 
striking  the  run-out  on  the  lower  side  and  acting  on  the  condensation  which 
is  endeavoring  to  flow  in  the  opposite  direction. 

The  most  surprising  fact  demonstrated  during  these  tests  was  the  rap- 
idly diminishing  effect  of  a  slope  greater  than  1  in  120  on  critical  velocity, 
and  the  indication  from  the  curves  plotted  for  the  entire  series,  that  the 
critical  velocity  was  little,  if  any,  greater  at  slopes  of  more  than  1  in  40 
than  at  that  slope.  It  follows  from  the  above  that  a  velocity  of  steam  which 
will  sweep  up  the  condensation  in  a  pipe  having  a  grade  of  1  in,  say,  33 
will  sweep  the  condensation  upward  in  a  pipe  having  more  grade. 

The  practical  application  of  this  series  of  tests  must  take  local  conditions 
into  consideration. 

The  thermal  capacity  of  the  mass  of  iron  in  a  cold  radiator,  will  call 
for  a  large  volume  of  steam  during  the  heating-up  period,  and  at  the  same 
time  the  difference  in  pressure  at  the  two  ends  of  the  run-out  will  be  greatest. 
Consequently  the  velocity  of  steam  through  the  run-out  will  be  far  greater 


i     Jx  Floor  Plate                                                                    Finished  Floor, 

Floor  P\ate-^ 

—  <_- 

T'1 

Q[                                                        I  F"'               ' 

f  * 

y 

\  9"  Pin*'                                                          «5=3; 

Riser-" 

~**—> 

Qx  Floor  Plate 

Finished  Floor^                                                                             Floor  Plates    f 

^  _^^= 

L, 

C 

-H 
i 

D3 

} 

i 

Fig.  12-1.  Illustrating  greater  capacity  of  largest  possible  run-out  pipe  at  a  minimum  grade  compared 
«ilh  Iliiil  of  smaller  pipe  tit  much  greater  grade.  The  capacity  of  2-in.  pipe  at  grade  of  %  in.  in  10  ft. 
is  greater  than  that  of  »  1-in.  pipe  at  1  J-g-in.  grade  in  10  ft.  in  the  ratio  of  7.20  to  t.35.  Note  application 
in  limited  span-  where  run-out  must  cross  structural  frame  beam 


133 


500  600  700  800  900  1000  1100  1200  1300  1400 

Velocity  in  Feet  per  Minute 

Fig.  12-2.  Critical  velocities  in  feet  per  minute,  of  low-pressure  steam  in  radiator  run-outs  at  various 
grades,  where  condensation  flows  down-grade  against  steam.  Specific  volume  of  steam,  about  26.5  cu. 
ft.  perlb. 

during  initial  heating-up  than  during  normal  maintenance. 

It  is  during  the  initial  heating-up  that  the  gurgling  and  hammering  of 
condensation  in  run-outs  causes  most  complaint.  It  is  then  that  the  flow 
of  steam  is  most  liable  to  exceed  the  critical  velocity  and  sweep  the  con- 
densation up  into  the  vertical  riser  pipe  to  the  inlet  valve. 

It  would  be  possible  to  use  a  run-out  of  half  the  area  of  cross-section 
if  the  radiator  is  to  be  constantly  hot  during  the  heating  season  as  compared 
with  area  of  run-out  at  same  grade  for  a  radiator  in  which  there  are  frequent 
alternations  of  heating  and  cooling.  Again,  there  are  many  installations  in 
which  a  little  noise  during  the  heating-up  period  would  not  be  considered 
objectionable,  while  in  others  the  same  amount  and  kind  of  noise  would 
condemn  the  entire  heating  system.  No  fixed  rule  based  on  square  feet  of 
radiation  may  therefore  be  made  for  sizing  run-outs  in  which  the  condensa- 
tion is  normally  drained  against  the  flow  of  steam. 

A  few  things  are  evident  from  these  tests  and  a  number  must  be  left 
to  the  good  judgment  of  the  designer  of  the  system  under  consideration. 

Among  the  evident  things  are: 

1.  That  a  uniform  grade  approximating  1  in.  in  10  ft.  is  about  the  maxi- 
mum useful  limit.  That  a  pipe  if  uniformly  graded  when  cold  is  liable  to 

134 


10       II        12 
B. t.  u.  per  Second 

Fig.  12-3.  B.t.u.  per  second  conveyed  in  low-pressure  steam  through  radiator  run-outs  at  grades  which 
are  critical  where  condensation  flows  against  the  current  of  steam.  Critical  velocities  established  by  test 
and  as  shown  in  Figure  12-2. 

buckle  upward  in  the  middle  when  hot  and  destroy  the  uniformity  of  grade. 

2.  That  the  most  constant  annoyance  will  occur  when  the  flow  of  steam, 
at  normal  maintenance  rate  exceeds  the  critical  velocity  for  the  grade  at 
which  the  run-out  is  laid. 

3.  That  where  noise  is  permissible  during  the  heating-up  period,  the 
run-out  should  be  sized  and  graded  so  as  not  to  exceed  the  critical  velocity 
during  any  normal  heat  maintenance.    If  so  sized  there  will  be  little  if  any 
noise  during  the  initial  period  when  condensation  is  being  swept  on  into  the 
radiator  by  a  velocity  materially  in  excess  of  about  1350  ft.  per  min.   There 
will,  however,  be  a  considerable  noise  as  the  heat  capacity  of  the  metal  in 
the  radiator  becomes  satisfied  and  this  will  continue  during  the  time  the 
steam  flow  is  at  a  velocity  of  about  1350  ft.  per  min.  until  the  steam  flow  falls 
below  the  critical  velocity  at  the  grade  of  the  run-out. 

From  the  above  tests  certain  practical  conclusions  may  be  inferred. 

The  practice  in  sizing  run-outs  has  been  based  on  some  relation  to 
pressure  drop  or  the  friction  of  the  steam  in  the  pipe.  This  more  properly 
applies  to  mains  and  risers. 

The  pressure  drop  due  to  friction  in  any  normal  run-out,  when  velocity 
is  low  enough  to  permit  the  current  of  condensation  to  flow  against  the 
si  cam,  is  less  than  .001  Ib.  per  ft.,  therefore  so  slight  that  it  is  negligible. 


135 


It  would  be  much  more  consistent  to  size  run-outs  on  basis  of  critical 
flow  rather  than  on  pressure  drop. 

Tables  1  and  2,  based  on  the  following  assumptions,  may  prove  of 
interest : 

1.  That  a  slight  noise  due  to  condensation  flowing  into  the  radiator 
with  the  steam  during  the  heating-up  period  will  not  be  objectionable. 

2.  That  at  maintained  rate,  the  condensation  in  the  vertical  rise  pipe 
must  also  flow  back  against  the  steam.    This  is  not  necessary  where  bottom 
of  the  inlet  to  the  radiator  is  at  a  higher  level  than  that  of  the  outlet. 

3.  That  the  radiation  during  maintenance  does  not  condense  at  a  rate 
in  excess  of  250  B.t.u.  per  sq.  ft.  per  hour. 

4.  That  there  will  be  a  uniform  grade  of  not  less  than  %  in.  in  10  ft. 
in  two-pipe  connection  and  1  in.  in  10  ft.  in  one-pipe  connection. 

Table  12-1.  Run-outs  for  Two-pipe  Work  Having  Grade  of  Not  Less  Than  %  in.  in  10 
ft.  Radiator  Transmits  Not  More  Than  250  R.t.u.  per  Sq.  Ft.  per  Hour 
at  Maintained  Rate. 

Size  of  pipe 1"          IX"       V4"  2" 

Maximum  radiation  on  pipe  in  sq.  ft. 


Horizontal  run-out  grade  %  in.  in  10  ft 43  101  173 

Vertical  branch  and  valve 58          108  144  260 


Fig.  12-2.  Run-outs  for  One-pipe  Work  Having  Grade  of  Not  Less  Than  1  in.  in  10 
ft.  Radiator  Transmits  Not  More  Than  250  R.t.u.  per  Sq.  Ft.  per  Hour 
at  Maintained  Rate. 


Size  of  pipe 1"         W  W  '• 

Maximum  radiation  on  pipe  in  sq.  ft. 

Horizontal  run-out  grade  1  in.  in  1 0  ft 25  50  68 

Vertical  branch  and  valve 35  75  100  170 


13H 


CHAPTER  XIII 

Vacuum  Pumps  and  Auxiliary  Equipment 

VACUUM  PUMPS  are  used: 
1.  To  remove  air  and  other  products  of  condensation  from  the  return 
main  where  these  products  cannot  be  expelled  to  atmosphere  by  gravity 
or  internal  steam  pressure  alone. 

2.  To  induce  circulation  by  reducing  the  pressure  in  the  return  main, 
thereby  increasing  the  pressure  differential. 

3.  To  assist  in  the  complete  disposal  of  the  products  of  condensation. 
Experience  indicates  two  successful  types  of  pump  for  this  service, 

namely,  reciprocating  steam-driven,  and  rotating  electric-driven.  The 
steam-driven  pump  has  efficiency  and  economy  in  its  favor  where  steam 
at  30-lb.  or  greater,  absolute  pressure,  is  continuously  available  and  the 
pump  exhaust  and  its  contained  heat  may  be  fully  utilized  in  the  system. 
The  electric-driven  pump  is  generally  most  efficient  where  exhaust  steam 
from  the  engines  and  other  sources  is  continuously  available  in  greater 
quantity  than  is  necessary  to  supply  the  heating  system;  in  other  words, 
where  the  exhaust  from  the  vacuum  pump  to  waste  would  be  a  loss.  The 
electric-driven  pump  is  also  preferable  where  the  available  live  steam  supply 
has  a  pressure  too  low  to  operate  a  steam-driven  pump. 

Many  rotating  pumps  in  which  both  air  and  water  were  handled  in 
one  chamber  have  deteriorated  very  rapidly  in  service,  largely  because  of 
the  grit  always  present  in  the  condensation.  Rotating  pumps  with  one  pump 
chamber  handling  air  and  vapor  and  another  containing  a  centrifugal 
impeller  for  handling  the  water  have  proved  practical. 

Many  variables  enter  the  problem  of  ascertaining  the  proper  size  of 
pump  for  a  given  heating  system.  In  the  final  analysis,  good  judgment 
based  on  wide  experience  in  applying  a  table  of  probable  pump  displace- 
ment is  of  far  greater  value  than  any  theoretical  formula. 

Even  for  a  close  approximation,  it  is  necessary  to  know  enough  about 
the  heating  plan  in  addition  to  "the  square  feet  of  equivalent  radiation"  to 
be  able  to  estimate  the  probable  maximum  volumes  in  unit  of  time  of  both 
water  and  elastic  fluids  of  condensation,  necessary  degree  of  vacuum  at  the 
pump  and  discharge  head  against  which  condensation  must  be  delivered. 

The  volume  of  water-condensation  varies  in  different  installations  fully 
40  per  cent  per  square  foot  of  equivalent  direct  radiation.  The  volume  of 
elastic  fluids — air,  water,  vapor,  steam  and  gases  from  impurities — also 
varies  with  the  initial  and  terminal  pressures,  with  the  efficiency  of  the 
radiator  traps,  with  the  degree  of  prevention  of  inward  leakage  of  air,  with 
the  probable  cooling  effect  in  the  return,  and  with  the  character  of  the  im- 
purities in  the  boiler-feed. 

Lifts  (see  Figure  13-1)  in  the  return  call  for  greater  terminal  vacuum 
with  consequent  greater  expansion  in  volume  of  the  elastic  fluids,  thus  calling 
for  greater  pump  displacement .  They  should,  therefore,  be  avoided  if  possible. 

Discharge  head  on  reciprocating  pumps  handling  water  and  air  has  the 

137 


Standard  conditions 

Steam  above  atmosphere  at  farthest  radiator 
Units  of  20  to  25  sq.  ft. 
Standard  screw-down  radiator  inlet  valves 
No  discharge  near  vacuum  pump  of  large  volume  of  condensation  at 
steam  temperature 
No  lifting  of  returns 
Returns  insulated 
Run  of  mains  less  than  500  ft. 
)  All  drip  points  have  Webster  Sylphon  or  No.  7  Traps 

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ation  to  pounds  of  condensation  per  hour 

Factory  pipe  coils  
Factory  wall  radiation  
Ix>w  cast-iron  radiators,  1  and  2  column  
Medium  height  cast-iron  radiators,  1  to  3-column  . 
High  cast-iron  radiators,  2  to  1  column  

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other  than  above 
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138 


effect  of  increasing  clearance  and  slip  and  thereby 
decreasing  the  effective  displacement. 

A  discharge  head  of  more  than  one  added 
atmosphere  on  reciprocating  pumps  is  best 
handled  by  separating  the  water  and  gases  and 
removing  them  independently  through 
two  separate  pumps. 

For  slip  in  reciprocating  wet-vacuum 
pumps  it  is  seldom  safe  to  allow  less  than 
Y§  of  the  displacement,  although  a  newly 
packed  pump  may 
show  much  less. 


Fig.  13-1.  Method  of  making  step-ups 
using  Webster  Series  20  Lift  Fittings. 
Pipes  between  lifts  must  grade  down- 
ward in  direction  of  arrows 


Systems  in  which  the  pressure  throughout  the 
supply  lines  and  radiation  as  well  as  in  the  re- 
turns is  normally  less  than  that  of  the  atmos- 
phere  are  subject  to  invisible  inleakage  of  air 
around  the  valves  and  fittings.  Such  systems 
require  increased  displacement  also,  because  of 
the  greater  volume  of  elastic  fluids  due  to  low  terminal  pressure  necessary 
for  circulation. 

Cooling  and  consequent  reduction  in  volume  of  the  elastic  fluids  in 
the  return  present  an  element  of  considerable  magnitude  and  uncertainty. 

Well-insulated  return  pipes,  also  large  volumes  of  condensation  entering 
the  main  return  close  to  the  vacuum  pump,  require  greater  displacement 
than  would  the  same  radiation  with  returns  in  which  a  considerable  portion 
of  the  vapors  could  condense  between  the  radiation  and  the  pump. 

Clearance  reduces  effective  displacement  in  all  pumps.  The  clearance 
for  a  given  cylinder  diameter  in  reciprocating  pumps  of  some  makes  is  ap- 
proximately the  same  in  short-stroke  as  in  long-stroke  pumps.  Commercial 
sizes  of  reciprocating  vacuum  pumps  vary  in  ratio  of  bore  to  stroke  between 
1  to  %  and  1  to  2;  it  follows  that  a  pump  of  the  latter  proportion  has  greater 
efficiency  per  displacement  than  the  short-stroke  pump  because  of  smaller 
percentage  of  clearance. 

Experience  with  reciprocating  steam-driven  vacuum  pumps  indicates 
that  for  most  favorable  conditions  the  use  of  water  cylinders  of  less  dis- 
placement than  eight  times  the  normal  volume  of  water  of  condensation  is 
seldom  safe.  With  radiation  divided  into  small  units,  a  ratio  of  at  least 
10  to  1  will  be  required. 

Ratings  for  the  rotating  combination  units  should  be  based  substan- 
tially on  a  10  to  1  ratio  of  the  combined  displacement  of  water  and  air  cylin- 
ders, the  ratio  of  these  cylinders  to  each  other  being  about  2  of  water  dis- 
placement to  8  of  air.  In  these  pumps  the  displacement  of  water  must  be 
high  on  account  of  the  constant  speed,  while  a  lower  proportion  of  air  dis- 
placement may  be  taken  because  of  the  high  efficiency  of  the  air  chamber 
as  compared  with  reciprocating  pump  cylinders  which  have  greater  clearance. 

The  speed  and  displacement  in  rotating  pumps  are  normally  constant, 
unless  expensive  variable  speed  motors  are  used,  whereas  in  reciprocating 

139 


steam-driven  pumps  piston  speed  may  be  varied  through  wide  range. 
The  temptation  to  gain  displacement  by  excessive  piston  speed  without 
regard  to  the  consequent  racking  of  the  pump  because  of  too  frequent 
starting  and  stopping  of  pistons  and  valves,  should  be  avoided  by  adhering 
to  a  definite  relation  between  piston  speed  and  length  of  stroke.  This 
relation  as  used  for  the  calculation  of  basic  ratings  expressed  in  column  2, 
Table  13-1  is  that  the  permissible  piston  speed  in  feet  per  minute  equals 
20  times  the  square  root  of  the  stroke  in  inches.  These  ratings  are  calcu- 
lated for  pumps  having  equal  stroke  and  bore  but  they  may  be  assigned  to 
other  pumps  as  will  be  explained  later.  The  relation  between  the  volume 
of  the  cylinder  and  that  of  the  water  discharged  per  stroke  is  figured  as 
ten  to  one.  Slip  is  assumed  to  be  one-sixth  of  the  total  stroke. 

The  following  example  will  fully  explain  the  method  of  calculations 
for  column  2. 

Selecting  from  column  1,  a  pump  having  4-in.  stroke  and  4-in.  bore, 
the  area  of  its  cylinder  is  4  x  4x  0.7854  =  12.568  sq.  in.,  or  0.0873  sq.  ft. 

The  piston  speed  is  20  x  V  4  =  40  ft.  per  min.,  or  2400  ft.  per  hr. 

The  gross  displacement  is  therefore  0.0873  x  2400  =  209.52  cu.  ft.  per 
hr.,  of  which  the  gross  water  displacement  is  one-tenth,  or  20.95  cu.  ft.  per  hr. 

Since  the  condensation  will  weigh  60  Ib.  per  cu.  ft.  at  about  200  deg. 
fahr.,  the  gross  water  displacement  may  be  expressed  as  20.95  x  60  ==  1257 
Ib.  per  hr.  This  must  be  reduced  one-sixth  because  of  slip,  or  to  1047  Ib. 
of  condensation  per  hr.  as  a  basic  rating  for  this  pump. 

Taking  the  average  B.t.u.  per  pound  of  condensation  as  970,  the  basic 
rating  for  the  same  pump  may  also  be  expressed  as  1,015,600  B.t.u.  per  hr. 

Ratings  for  vacuum  pumps  are  properly  expressed  only  in  terms  of 
pounds  of  water  condensed  by  the  heating  system  in  a  given  period  of  time, 
or  the  equivalent  latent  heat  in  B.t.u.  given  up  by  the  steam  while  con- 
densing. Ratings  in  terms  of  "square  feet  of  direct  radiation"  are  not 
strictly  correct  and  may  be  misleading  since  there  is  not  recognition  of 
steam  pressures,  temperature  difference,  and  other  factors  entering  the 
problem.  However,  for  convenient  use,  factors  are  shown  at  the  lower  left 
of  Table  13-1  for  reduction  of  square  feet  of  various  types  of  radiation  to 
pounds  of  condensation  per  hour  which  will  give  approximate  results. 

Since  many  vacuum  pumps  may  have  unequal  stroke  and  bore,  the 
capacity  factors  in  column  12  are  provided  to  show  the  relative  effective- 
ness of  such  pumps  as  compared  with  "square"  pumps  having  same  bore 
and  equal  stroke.  Column  11  shows  relative  proportions  of  "unequal" 
pumps  in  terms  of  stroke  divided  by  bore.  The  corresponding  factor  for  a 
pump  of  any  selected  relation  of  stroke  to  bore  is  found  directly  across  in 
column  12. 

These  factors  provide  means  for  selection  of  stock  size  pumps  where 
the  rate  of  condensation  to  be  handled  is  intermediate  between  basic  rates 
for  "square"  pumps  stated  in  column  2. 

For  instance,  assume  a  condensation  rate  of  15,000  Ib.  per  hr.  To  find 
the  proper  size  of  pump,  select  the  diameter  of  bore  in  column  1  correspond- 
ing to  the  basic  rate  in  column  2  nearest  equal  to  the  required  rate.  This 

140 


basic  rate  is  16,300  Ib.  per  hr.  and  the  bore  is  12-in.  Then  find  the  factor 
in  column  12  equal  to  the  quotient  of  required  rate  divided  by  the  basic 
rate  for  the  12-in.  pump.  This  quotient  is  0.92  and  the  nearest  equivalent 
factor  in  column  12  is  0.91.  The  corresponding  figure  in  column  11  is  0.80 
which  is  the  decimal  relation  of  stroke  divided  by  bore. 

Multiply  the  bore  (12-in.)  by  the  factor  (0.80)  and  it  is  found  that  the 
stroke  should  be  9.6-in.  The  nearest  equivalent  stock  size  of  pump  has 
10-in.  stroke  and  therefore  a  12-in.  x  10-in.  pump  is  selected. 

Where  the  result  of  such  a  calculation  does  not  fit  obtainable  stock 
sizes,  select  a  stock  pump  of  some  other  diameter  and  stroke  which,  when 
factored  by  use  of  column  12,  will  give  a  rating  at  least  equal  to  that  required. 

Another  problem  is  that  of  finding  the  basic  rating  for  any  given  pump 
of  unequal  stroke  and  bore;  for  instance,  one  having  4-in.  bore  and  6-in. 
stroke. 

The  relation  of  stroke  to  bore  is  6  divided  by  4  or  1.5.  Finding  the 
number  1.5  in  column  11  it  is  noted  that  the  corresponding  factor  in  column 
12  is  1.19.  Multiplying  1.19  by  1047,  which  is  the  basic  rating  for  a  4-in. 
x  4-in.  pump  from  column  2,  the  product  gives  1246  Ib.  of  condensation 
per  hr.  as  the  basic  rating  for  this  4-in.  x  6-in.  pump. 

It  is  to  be  specially  noted  that  the  basic  ratings  shown  in  column  2 
are  calculated  and  shown  for  the  standard  conditions  of  operation  stated  in 
the  upper  right  of  the  table.  Other  actual  or  expected  conditions  of  opera- 
tion can  be  transformed  to  terms  of  standard.  Where  the  B.t.u.  to  be 
emitted  are  individually  calculated  for  each  group  of  like  class  and  size  of 
radiation,  these  quantities  may  be  multiplied  by  the  factors  in  column  13 
or  divided  by  those  in  column  14.  The  sum  of  these  factored  quantities  will  be 
the  basic  rating  (column  2)  from  which  the  size  of  water  cylinder  is  selected. 

Under  conditions  requiring  lift  points  in  the  return;  or  where  there  is 
inleakage  around  inlet  valves  or  elsewhere;  or  where  large  volumes  of  high 
temperature  returns  enter  near  the  pump ;  or  if  the  run  of  piping  from  source 
of  steam  supply  to  farthest  radiator  is  long;  or  where  the  radiator  traps  leak 
steam ;  additional  factors  must  be  applied  to  insure  the  proper  size  of  pump. 
These  factors  cannot  be  summarized  since  their  selection  is  entirely  a  matter 
of  judgment  and  of  experience  with  similar  conditions. 

Column  4  shows  the  minimum  size  for  return  main  entering  pump. 
These  sizes  are  based  upon  a  grade  in  the  piping  of  1  ft.  in  300  toward  the 
pump  and  upon  a  condition  where  the  return  pipe  is  half-full  of  water  and 
will  then  discharge  condensation  by  gravity  at  rates  not  less  than  the  basic 
rates  in  column  2.  For  these  calculations,  the  Chezy  formula  Q  =  a  c  V  r  s 
is  used,  in  which  Q  is  the  quantity  discharged,  a  is  the  cross-sectional  area 
of  the  pipe,  r  is  the  hydraulic  radius,  s  is  the  hydraulic  slope  of  the  pipe 
and  c  is  a  coefficient. 

The  size  of  returns  inlet  from  column  4  will  also  determine  the  size  of 
suction  strainer  which  is  to  be  used  in  this  main  at  the  pump. 

Column  5  is  calculated  from  the  same  formula  to  determine  the  mini- 
mum size  of  pump  discharge  and  delivery  pipe  from  pump  to  air-separating 
tank.  In  this  case  the  pipe  is  considered  to  be  half-full  of  water  and  its 
grade  is  1  in.  in  20  ft. 

141 


For  purposes  of  determining  the  proper  size  of  air  separating  tank  to 
apply  for  a  given  rate  of  condensation  discharge  from  pump,  the  assumption 
is  made  from  field  experiences  that  1  sq.  ft.  of  liberating  surface  should  be 
provided  under  average  conditions  for  each  2100  Ib.  of  water  discharged 
per  hour.  Column  6  of  Table  1  shows  the  number  of  square  feet  of  liberat- 
ing surface  required  for  the  basic  discharge  ratings  in  column  2. 

Where  the  tank  is  used  only  for  air-separating  purposes  such  as  plain 
tanks  and  hydro-pneumatic  tanks,  the  sizes  of  tanks  may  be  designed 
directly  from  the  figures  in  column  6.  Dimensions  of  tanks  following  this 
design  are  shown  in  columns  7  and  8. 

In  cases  where  the  tank  is  used  for  storage  of  returns,  the  tank  should 
be  larger  than  that  required  for  purposes  of  air-separation  only.  Columns 
9  and  10  show  dimensions  of  such  tanks  based  upon  storing  the  quantities 
of  water  which  will  be  discharged  during  five  minutes  at  the  basic  hourly 
rates  shown  in  column  2. 

As  an  example  of  the  complete  calculations  for  sizing  the  water  end  of 
a  vacuum  pump  and  for  selecting  size  of  auxiliary  equipment,  assume  a 
group  of  three  buildings,  A,  B  and  C,  from  which  condensation  flows  at 
rates  of  7500,  5000  and  3000  Ib.  per  hr.  respectively. 

Also  assume  that  the  7500  Ib.  per  hr.  of  condensation  in  building  A  is 
from  blast  coils  and  a  closed  heater;  that  the  5000  Ib.  per  hr.  from  building 
B  is  from  pipe  coils,  each  containing  130  sq.  ft.;  that  the  3500  Ib.  per  hr. 
from  building  C  is  from  direct  radiators  in  50  sq.  ft.  units;  that  return 
mains  are  exposed ;  and  that  it  is  proposed  to  use  a  plain  type  of  air  sepa- 
rating tank. 

These  condensation  rates  must  be  transformed  to  those  which  would 
be  realized  under  the  standard  conditions  upon  which  this  table  is  based,  by 
means  of  the  factors  in  column  13,  using  0.66  for  blower  stacks  and  closed 
heater,  0.70  for  coils  larger  than  120  sq.  ft.  and  0.84  for  radiator  units  of 
50  sq.  ft.  By  applying  these  factors  the  equivalent  condensation  rates  are 
found  to  be  4950,  3500  and  2940  Ib.  per  hr.  for  building  A,  B  and  C  re- 
spectively or  11,390  Ib.  per  hr.  for  the  transformed  equivalent  total  rate. 

From  column  2,  the  nearest  basic  rate  is  10,350  Ib.  per  hr.  and  from 
column  1,  the  corresponding  diameter  of  bore  for  this  pump  is  10-in. 

By  dividing  the  required  rate  11,390  by  the  basic  rate  10,350,  the 
capacity  factor  is  found  to  be  1.10.  Going  into  the  table  it  is  found  that 
1.10  in  column  12  corresponds  with  a  relation  of  stroke  to  bore  of  1.25 
(column  11).  Multiplying  1.25  by  10  in.  (the  bore)  gives  12.5  in.  as  the 
required  stroke.  The  nearest  stock  size  is  12-in.  stroke  so  that  a  pump 
having  10-in.  bore  by  12-in.  stroke  is  selected. 

From  columns  4  and  5,  the  minimum  requirements  for  size  of  returns 
inlet  and  discharge  for  this  pump  are  found  to  be  4  in.  and  2^2  m-  respec- 
tively. If  the  return  main  is  long,  it  is  better  to  select  5-in.  as  the  minimm 
size  of  return  inlet,  since  4^-in.  is  not  a  regular  stock  size  for  pipe  and 
fittings.  The  suction  strainer  will  be  the  same  size  as  the  return  main 
entering  the  pump. 

Selecting  from  columns  7  and  8,  the  size  of  plain  air-separating  tank  is 
18-in.  diameter  by  48-in.  length. 

142 


PROPORTIONING  OF  STEAM  ENDS  OF  RECIPROCATING  VACUUM  PUMPS: 
In  proportioning  the  steam  cylinder,  the  following  is  a  safe  rule  to  use. 
The  area  of  the  steam  cylinder  in  square  inches  limes  one-third  the  boiler  pres- 
sure should  equal  the  water  piston  area  in  square  inches,  multiplied  by  the 
combined  pressure  on  the  water  end  (vacuum  plus  discharge  pressure)  expressed 
in  pounds  per  square  inch.  This  is  given  by  the  following  equation: 


From  which  we  have 

Aw  X  (|  +  Pd)  X  3 


(Formula  13-1) 


in  which 

A.  =  area  of  steam  piston  in  square  inches. 
Aw  =  area  of  water  piston  in  square  inches. 
Pb  =  boiler  pressure  in  pounds  per  square  inch. 
Pd  =  discharge  pressure  in  pounds  per  square  inch. 
V     =  vacuum  at  pump  expressed  in  inches  of  mercury. 

V 

-S-—  approximate  vacuum  in  pounds  per  square  inch  (2  in.  mercury  = 

approximately  1  Ib.  per  sq.  in.) 

Note:  All  pressures  are  by  gauge. 

In  the  above  formula,  the  working  pressure  is  taken  as  one-third  of 
the  boiler  pressure,  in  order  to  allow  for  the  low  mechanical  efficiency  of 
the  pump,  as  well  as  for  the  inevitable  drop  in  steam  pressure  between  the 
boiler  and  the  inlet  of  the  pump.  Carelessness  in  setting  up  the  packing 
in  the  water-and-air  piston  is  prevalent  and  to  be  expected.  It  is  also 
necessary  for  the  pump  to  keep  going  even  when  the  boiler  pressure  may 
be  considerably  lower  than  the  normal  working  pressure. 

While  in  some  cases  this  formula  may  give  dimensions  which  appear 
to  be  larger  than  necessary,  it  is  seldom  safe  to  make  the  area  of  the  steam 
cylinder  less  than  twice  the  area  of  the  water-and-air  cylinder. 

Column  3  of  Table  13-1  shows  sizes  of  steam  supply  and  of  vacuum 
governor,  for  boiler  pressure  of  75  to  125  Ib.  per  sq.  in. 

POWER-DRIVEN  RECIPROCATING  VACUUM  PUMPS:  Lack  of  available 
steam  pressure  to  operate  the  piston  in  reciprocating  vacuum  pumps  requires 
that  some  other  source  of  power  must  occasionally  be  utilized.  Where  this 
is  the  case,  a  reciprocating  pump  is  in  many  cases  unsuitable  because  of  the 
difficulty  in  handling  the  varying  load  during  each  stroke  and  because  no 
satisfactory  means  for  controlling  the  displacement  to  maintain  the  desired 
degree  of  vacuum  has  yet  been  devised  for  this  type  of  pump. 

To  move  the  reciprocating  piston  in  the  water  cylinder  by  means  of  a 
connecting  rod  and  crank,  the  latter  necessarily  rotating  at  low  speed, 
entails  gearing  or  an  extremely  large  pulley  and  countershafting.  Inasmuch 
as  the  torque  varies  from  almost  nothing  at  the  ends  of  the  stroke  to  a  high 
maximum  at  about  three-fourths  stroke,  back-lash,  noise  and  wear  of  gears 

143 


or  slapping  and  slip  of  belts  are  to  be  expected  unless  a  heavy  fly-wheel  is 
used,  and  in  any  instance  the  power  consumption  is  excessive. 

Variable-speed  motors  are  sometimes  utilized  for  driving,  but  are 
expensive,  and  give  only  two  or  three  steps  of  displacement,  which  must  be 
selected  either  manually  or  by  complicated  delicate  electrical  controllers. 

There  is  nothing  to  commend  in  intermittent  control.  Constant  speed 
and  displacement  with  a  vacuum  breaker  to  admit  air  when  the  load  is 
below  normal  is  probably  nearest  to  a  satisfactory  arrangement  where 
power-driven  reciprocating  vacuum  pumps  are  used. 

DISPOSAL  OF  VACUUM  PUMP  DISCHARGE:  Conditions  vary  to  such  an 
extent  that  good  judgment  is  the  only  safe  guide  in  determining  the  best 
method  for  the  disposal  of  the  vacuum  pump  discharge.  In  no  case  should 
the  head  against  the  discharge  of  reciprocating  pumps  exceed  15  Ib. 
unless  the  pump  stroke  materially  exceeds  the  bore  and  thus  reduces  the 
bad  effect  of  clearance.  Usually  one  of  these  seven  methods  will  best  apply : 

1.  Discharge  to  Waste:   Disposal  by  discharge  to  waste  involves  loss  of 
all  the  valuable  heat  and  water,  but  in  rare  cases  this  is  permissible. 

2.  Discharge  through  Air-separating  Tanks:    Where  first  thought  seems 
to  suggest  disposal  to  waste,  it  will  in  many  cases  be  found  possible  to 
deliver  the  water  and  air  into  a  separating  tank,  or  stand  pipe  sufficiently 
elevated  for  the  water,  after  separation,  to  flow  by  gravity  to  some  point  of 


Vent  to  Atmosphere 


WEBSTER  PLAIN    I  I  To  Feed-water 
RECEIVING  TANK         Heater  through 
I  Loop  Seal  or  as 
-Directed 


_  Steam  to 
Vacuum  Pump 

lobe  Valve 


WEBSTER  LIFT  FITTING 
Fig.  13-2.     Method  of  connecting  vacuum  pump  to  a  plain  receiving  tank 


144 


valuable  use,  such  as  boiler  or  feed-water  heater,  etc.,  or  for  hot  water  supply. 

Where,  due  to  structural  conditions,  a  suitable  elevated  location  cannot 
be  found,  the  effect  of  head  may  be  obtained  by  use  of  a  hydro-pneumatic 
tank  as  described  under  heading  No.  4. 

3.  Discharge  to  Open  Vent  Tanks:  Open  vent  tanks,  otherwise  called 
plain  separating  tanks,  normally  serve  the  purpose  of  releasing  the  entrained 
air  from  the  discharge  of  the  vacuum  pump.  (See  Figure  13-2.) 

This  air  removal  requires  the  generous  water  surface  area  of  either  a 
tank  of  large  horizontal  cross-section,  rather  than  one  of  large  vertical 
sectional  area,  or  a  tank  with  a  large  vertical  head  and  enough  sectional 
area  to  permit  of  low-velocity  downward  water  flow  while  entrained  air  is 
floating  to  the  surface  against  the  water  current,  as  in  a  stand  pipe.  For 
removal  of  ah-,  one  square  foot  of  horizontal  cross-section  has  usually  been 
found  suilicient  for  each  2100  Ib.  of  water  per  hour.  A  stand  pipe,  with 
diameter  equal  to  that  of  the  pump  cylinder,  is  usually  sufficient,  although 
a  more  logical  rule  is  to  make  the  cross-sectional  area  of  the  stand  pipe 

Water  Control  Valve 
Cold  Water  Connection 


Overflow  to  Wiste 


Discharge  from 
Vacuum  Pump 


Multiply  maximum  back  pressure 
carried  in  heater  by  3  to  determine 
least  dimension  in  feet 


Fig.  13-3.   Typical  application  of  Webster  Water-control  Receiving  Tank  in  connection  with  an  open  feed- 
water  heater.   The  heater  should  be  set  on  a  foundation  of  sufficient  height  (a  vertical  rise  of  not  less  than 
three  feet)  between  the  pump  outlet  of  the  heater  and  the  suction  valves  of  the  boiler-feed  pump 

145 


bear  some  direct  relation  to  the  amount  of  condensation  from  which  the  air 
is  to  be  separated,  and  to  the  height  of  column  of  water  through  which  the 
air  bubbles  must  rise  against  the  flow  of  liquid. 

The  fact  that  the  discharge  of  reciprocating  wet-vacuum  pumps  is  a 
mixture  of  water  and  air  favors  the  use  of  a  freely  vented  separating  tank 
wherever  a  suitable  location  may  be  obtained.  This  is  such  height  that 
the  pressure  produced  by  the  water  column  will  be  sufficient  to  overcome 
that  in  the  low-pressure  boiler,  feed-water  heater  (see  Figure  13-3),  or 
other  point  of  disposition. 

The  effective  column  or  head  between  the  pump-discharge  valve  and 
the  inlet  of  the  separating  tank  will  be  less  than  that  of  solid  water  by  the 
volume  of  air  contained  in  the  mixture.  The  contents  in  separating  tank 
and  discharge  pipe  therefrom  will  be  water  only.  It  is,  therefore,  possible 
with  pump  discharge  properly  proportioned  and  provided  with  lift  fittings, 
vertical  rise  pipe  to  tank,  etc.,  to  obtain  a  gravity  head  in  the  tank  discharge 
above  the  level  of  the  pump  valve  deck,  considerably  greater  than  the  pres- 


Vent  to  Atmosphere 


Automatic  Air  Vent  Valve 


Automatic  Water  Relief 
Valve  and  Overflow 


To  Drain  unobstructed 
Funnel 


,  Connection  from  Low  Pressure 
Steam  Main  to  Steam  Gauge 


-Vacuum  Pump  Discharge 


Return  to  Boiler 


Motor 


WEBSTER  LIFT  FITTINGS 


Fig.  13-4.    Method  of  connecting  geared-type  vacuum  pump  and 
Webster  Single-control  Hydro-pneumatic  Tank 

146 


sure  in  the  pump  cylinder  necessary  to  lift  the  valves  and  discharge  the  con- 
densation to  the  elevated  return  tank. 

4.  Discharge  to  Hydro-pneumatic  Tanks:  As  the  name  indicates,  hydro- 
pneumatic  tanks  bring  the  elastic  pressure  of  the  liberated  air  to  act  on 
and  supplement  the  head,  in  the  discharge  of  the  water  of  condensation. 
A  float-controlled  valve  is  placed  on  the  air  outlet  of  the  separating  tank, 
and  so  arranged  that  when  the  water  of  condensation  has  not  sufficient 
head  to  flow  by  gravity  to  the  point  of  use,  the  air  will  be  confined  in  upper 
part  of  tank.  As  the  pump  continues  to  deliver  water  and  air  to  the  tank 
(see  Figure  13-4)  the  pressure  inside  the  tank  increases  until  sufficient  to 
discharge  the  water,  thus  lowering  the  water  line  and  eventually  permitting 
escape  of  the  surplus  air  through  the  float-controlled  air  valve. 

The  discharge  of  condensation  to  low-pressure  boilers,  in  which  the  pres- 
sure may  at  times  be  less  than  that  of  the  atmosphere,  requires  another 
float  in  the  hydro-pneumatic  tank  (see  Figure  13-5)  to  control  the  valve 
on  the  tank  water  discharge  and  keep  this  pipe  closed  at  such  times  as  there 
might  be  danger  of  air  flowing  from  the  tank  to  the  boiler. 

The  hydro-pneumatic  type  of  tank  is  used  only  where  an  open  tank 
cannot  be  located  at  a  height  sufficient  to  provide  gravity  head  to  discharge 
the  tank  contents  against  the  maximum  pressure  in  the  heater  or  boiler,  or 


Vent  lo  Atmosphere 


tomatic  Air  Vent  Valve 


Automatic  Water  Relief 
Valve  and  Overflow 


WEBSTER 
HYDRO-PNEUMATIC  TANK 


Equalizing  Line  connect  to 

Boiler  at  Point  having  no 

Steam  Flow 


'      Connection  from  Low 
Pressure  Steam  Main 
to  Steam  Gauge 


Check  Vilve-Dfain,oSewer     WEBSTER  SUCTION  STRAINER 
Fig.  13-5.     Typical  connections  to  vacuum  pump,  double-control  hydro-pneumatic  tank  and  boiler  feeder 

147 


where  there  are  large  variations  between  the  maximum  and  minimum  pres- 
sures to  be  overcome.  Where  the  hydro-pneumatic  tank  is  used  merely  as 
a  substitute  for  an  open  separating  tank,  little  advantage  may  be  taken  of 
the  light  density  of  the  pump  discharge. 

The  confined  air  pressure  in  the  hydro-pneumatic  tank  plus  the  gravity 
head  in  the  tank  discharge  pipe  must  be  sufficient  to  cause  flow  to  the  place 
of  disposition.  This  confined  air  pressure  plus  the  column  of  mixed  air  and 
water  in  the  pump  discharge  to  the  tank  is  the  total  head  against  which 
the  pump  must  act. 

Where  pressure  on  the  heater,  boiler,  etc.,  varies  materially  from  time 
to  time,  but  in  general  is  near  the  minimum,  a  substantial  saving  in  energy 
may  be  obtained  by  using  a  hydro-pneumatic  tank  instead  of  a  plain  tank 
set  at  higher  elevation  to  overcome  the  peak  pressure  in  the  boiler  or  heater. 
The  use  of  a  plain  tank  under  these  conditions  keeps  the  pump  operating 
constantly  against  the  maximum  head,  where  a  hydro-pneumatic  tank  set 
lower  operates  as  a  plain  tank  whenever  the  gravity  head  in  the  tank  is 
sufficient  to  cause  flow  at  the  low  elevation,  and  employs  the  combination 
of  air  pressure  and  gravity  head  (with  air  vent  closed)  only  at  times  of  peak 
load.  Only  then  is  the  air  pressure  load  added  to  the  pump  discharge. 

5.  Discharge  to  Loop  Seal  on  Tank  Outlet  to  Heater  or  Boiler:  The  dis- 
posal of  water  of  condensation  from  a  return  tank  to  a  feed  heater  (see 
Figure  13-3),  boiler  or  other  receptacle,  in  which  there  may  be  greater  pres- 
sure than  that  of  the  atmosphere,  requires  guarding  against  back  flow  of 
steam,  air  or  whatever  other  elastic  fluid  may  be  present  at  the  outlet. 

A  loop  seal  has  been  found  most  suitable  for  this  purpose,  provided  the 
seal  is  made  long  and  contains  ample  volume  in  the  vertical  leg  on  the 
pressure  side.  A  variable  pressure  when  increasing  tends  to  force  the  level 
of  water  down  in  the  leg  on  the  pressure  side  and  up  in  the  leg  toward  the 
tank.  If  there  is  not  sufficient  water  in  the  loop,  the  water  will  become 
displaced,  and  the  seal  broken  before  enough  of  a  water  column  has  been 
built  up  in  the  leg  from  the  tank.  The  column  will  then  blow  into  the  return 
tank  and  the  steam  or  other  elastic  fluid  will  continue  to  blow  while  its 
pressure  is  above  that  at  the  tank  outlet. 

The  fact  that  water  in  the  tank  is  ready  to  seal  the  loop  below  will 
not  avail  as  long  as  there  is  a  difference  in  pressure  between  the  tank  and 
boiler  sufficient  to  blow  a  comparatively  short  slug  of  water  back  into  tank. 
The  only  way  to  restore  the  seal  is  first  to  equalize  the  pressure  on  both 
legs.  A  good  practice  is  to  proportion  the  leg  on  the  pressure  side  to  hold 
twice  the  contents  of  the  pipe  from  the  tank  to  the  bottom  of  the  seal. 

6.  Discharge  to  Receiver  and  Boiler-feed  or  Tank  Pump:  Where  the  head 
on  the  delivery  side  of  steam-driven  vacuum  pumps  exceeds    15  lb.,  it 
is  good  practice  to  deliver  the  condensation  to  a  vented  receiver  (see  Figure 
13-6)  located  close  to  the  level  of  the  vacuum-pump  outlet.     This  receiver 
should  be  connected  to  a  separate  steam  or  power-driven  water  pump  which 
is  capable  of  delivering  against  the  maximum  head.    (See  Figure  13-7.)   If  this 
pump  is  steam-driven,  its  displacement  should  be  controlled  by  a  throttle 
valve,  actuated  by  the  water  line  in  the  receiving  tank;  if  power-driven,  the 
effective  displacement  may  best  be  controlled   by   bypass  valve  between 

148 


^-Discharge  from  Vacuum  Pump 


lobe  Valve 


Lubricator 


WEBSTER  COMBINATION  GAUbES 
Globe  Valve_^j_ti  ; 


Connection  from  Low 
Pressure  Steam  Main  to 
Steam  Gauge 


Boiler  Feed  Pump 
and  Receiver 


Drain  to  Sewer 
Check  Valve 


WEBSTER  LIFT  FITTING 
rig.  13-6.     Method  of  connecting  vacuum  pump  and  automatic  boiler-feed  pump  and  receiver 


Vent  to  Atmosphere 
Bun  to  Air  above  Roof- -4* 


Connection  Irom  Low 

Pressure  Steam  Main 

to  Steam  Gauge 


.  Japping  in  Top 
ot  Water  End. 
Connect  with 

ischarge 
Line  lor  Air  Relief 


Lubricator 
Globe  Valve 


WEBSTER  LIFT  FITTING^  To  Sewer        WEBSTLR  SUCTION  STRAINER 

Fig.  13-7.    Method  of  connecting  vacuum  pump,  boiler-feed  pump  and 
Webster  Steam-control  Receiving  Tank 

149 


pump  suction  and  delivery,  and  actuated  by  water-line  float  in  the  receiver. 

7.   Dry-vacuum  Pump  Receiver  and  Water  Pump:    This   combination 

proves  very  effective  under  conditions  of  high  delivery  head  where  the  main 


Connection  from  Low  Pressure 
Steam  Main  to  Steam  Gauge 

WEBSTER 
COMBINATION  GAUGES 


Tr^Globe  Valve 


Globe 
Valve 


Lubricator 


ijf.  13-8.     Method  of  making  connections  to  steam-operated  vacuum  pump 


return  can  be  arranged  to  flow  by  gravity  to  a  closed  receiver,  which  in  turn 
is  sufficiently  elevated  above  the  location  of  water  pump  to  provide  a  head 
of  2  to  3  Ib.  on  the  pump  inlet  valves. 

The  dry-vacuum  pump  being  free  from  dirt  and  abrasive  material,  may 
have  close  clearance  and  fairly  high  efficiency.  It  may  be  located  above 
and  take  its  suction  from  the  top  of  the  receiver,  and  frequently  some  form 
of  condenser  may  be  arranged  in  the  suction  line  to  absorb  and  utilize  other- 
wise wasted  heat  from  the  air  and  water  vapor  and  at  same  time  materially 
reduce  the  volume  of  vapor  to  be  handled. 

The  receiver,  if  properly  designed,  forms  a  receptacle  for  the  grit  and 
impurities  which  would  otherwise  injure  the  water  pump;  and  it  also  affords 
space  for  a  float  governor  for  controlling  the  water  pump  by  the  varying 
volume  of  return  water. 

Excessive  vacuum  in  the  receiver  will  cause  trouble  in  the  water  pump. 
For  this  reason,  a  vacuum  governor  should  always  be  used  to  control  the 
dry-vacuum  pump  and  to  hold  the  vacuum  within  pre-determined  limits. 


1.50 


WEBSTER 
VACUUM  GOVERNOR 


SUCTION  STRAINERS:  The  worst  of  the  grit  and 
dirt  from  condensation  should  be  retarded  and  re- 
moved before  entering  the  pump  where  it  would 
score  the  water  cylinder.  Strainers  (see  Figure 
13-8)  with  readily  removed  baskets  for  use  on  the 
main  vacuum  return  line  were  first  designed  and 
recommended  by  Warren  Webster  &  Company  24 
years  ago.  The  original  Webster  design  with  little 
modification  has  been  almost  universally  adopted. 

In  some  instances,  conditions  arise  where  large 
quantities  of  returns,  at  unusually  high  tempera- 
tures, are  discharged  into  the  line  near  the  vacuum 
pump.  These  may  come  from  special 
apparatus  such  as  cooking  or  hospital 
li \lures,  dry  kilns,  or  other  devices 
using  high  pressure  steam.  A  combi- 

.  .  %  .  .  .  i  i        V4  Vacuum  Line  to  Vacuum 

nation  of  suction  strainer  and  a  cook-  G,urje  and  suction  strainer 
ing  device,  shown  on  page  262,  will  be 
found  to  be  of  advantage,  particularly 
where  it  is  desired  to  carry  a  high 
vacuum  at  the  pump.  Cold  water, 
passing  through  copper  coils,  is  used 
to  condense  the  vapor  in  the  main  re- 
turn. 

VACUUM  GOVERNORS:  In  steam- 
driven  pumps,  control  of  displacement 
by  the  degree  of  vacuum  maintained  in 
the  return  line  may  be  effectually  ac- 
complished by  throttling  the  steam 
supply.  (See  Figure  13-9.)  Simple 
forms  of  diaphragm-actuated  throttle 
valves  will  control  the  degree  of 


Uve  Steam  from 
Boiler 


Plug 


Fig.  13-9.    Connections  for  a  Webster  Vacuum- 
pump  Governor 


vacuum  in  the  main  return  within  sufficiently  narrow  limits  for  all  practical 
purposes. 


151 


152 


CHAPTER  XIV 

Laboratory  Tests  of  Return  Traps 

THE  object  of  laboratory  tests  of  appliances  is  to  determine  the  efficiency 
of  the  apparatus  tested,  as  a  guide  to  judgment  in  selecting  materials 

or  in  the  case  of  technical  schools,  as  a  part  of  the  instruction  of  the 
students  in  methods  of  scientific  research. 

All  of  the  operating  conditions  possible  or  probable  in  an  actual  heating 
system  cannot  be  artificially  produced  in  the  laboratory,  nor  is  it  practical 
to  carry  out  tests  long  enough  or  upon  sufficient  numbers  of  samples  to  learn 
all  facts  which  become  evident  in  practice.  Furthermore,  as  the  whole 
heating  system,  including  design  and  installation,  has  its  effect  upon  the 
efficiency  of  the  devices  entering  into  it  as  parts,  any  laboratory  tests  for 
efficiency  can  indicate  only  the  results  which  are  probable  when  the  devices 
are  properly  used  in  practice. 

Too  much  stress  should  not  be  laid,  therefore,  upon  the  comparative 
performances  of  any  two  makes  of  traps  during  laboratory  tests.  Knowl- 
edge of  performances  in  actual  installations  of  many  heating  systems, 
maker's  ability  and  care  in  manufacturing,  shop  tests,  inspection  and  proper 
engineering  application  of  the  traps  are  of  great  importance  to  the  investi- 
gator who  wishes  to  make  commercial  use  of  his  study  of  such  devices. 

However,  as  laboratory  tests  have  their  useful  place  in  commercial 
investigation,  the  various  types  of  traps  and  the  results  of  tests  which  may 
be  expected  are  outlined  in  this  chapter.  Mention  is  made  of  many  com- 
mon forms  of  tests  which  give  erroneous  results  so  that  these  errors  may 
be  avoided.  Methods  and  apparatus  for  reliable  tests  are  jnentioned  and 
illustrated. 

Usually  the  object  of  a  laboratory  test  of  a  return  trap  is  to  determine 
one  or  all  of  the  following  characteristics: 

1.  Effect  of  the  trap  upon  radiator  efficiency. 

2.  Efficiency  of  the  trap  for  the  removal  of  air  and  water  of  condensation 
and  for  conservation  of  steam  and  vapor. 

3.  Behavior  of  the  trap  without  special  adjustment  to  meet  the  varying 
conditions  of  pressure  and  vacuum  in  normal  practice. 

4.  Durability  of  the  trap  through  a  long  period  of  use. 

5.  Construction  features  of  the  trap,  particularly  the  amount  of  valve 
movement,  which  indicates  the  ability  to  get  rid  of  dirt  and  pipe  scale. 

The  results  of  tests  by  many  investigators,  of  radiator  and  trap  effi- 
ciency, have  varied  widely  and  have  often  been  misleading,  largely  because 
the  methods  of  testing  have  been  faulty  and  partly  because  the  devices 
themselves  have  not  always  been  manufactured  to  operate  uniformly. 

Most  tests  of  which  the  results  have  been  published  have  been  faulty 
through  failure  to  cover  a  wide  enough  variety  of  test  conditions,  through 
limitation  of  the  time  period  for  each  test  to  a  few  minutes  instead  of  hours, 
and  through  considering  and  testing  only  one  or  two  samples  of  any  one 

153 


device,  instead  of  six  or  more  selected  by  the  investigator  from  the  manu- 
facturer's stock  bins  or  purchased  in  the  open  market. 

TESTS  FOR  HEATING  EFFICIENCY:  The  heating  efficiency  of  a  radiator 
depends  upon  physical  conditions  within  the  radiator  which  are  affected  by 
the  action  of  the  return  trap.  The  radiator,  among  a  number  of  common 
size  and  type,  which  maintains  the  highest  average  temperature  when 
tested  under  the  same  conditions,  is  the  most  efficient. 

The  greatest  possible  steam  economy  is  obtained  where  this  efficiency 
is  highest;  that  is,  where  steam  is  being  condensed  to  the  greatest  extent 
possible  within  the  radiator  and  the  trap  passes  the  least  amount  of  steam  or 
vapor  into  the  return  pipe. 

The  highest  radiator  efficiency  can  be  obtained  only  where  the  dis- 
charge is  sufficiently  and  properly  restricted  to  prevent  steam  from  blowing 
into  the  return.  Also  the  air  released  from  the  steam  in  the  radiator  must 
be  allowed  to  settle  to  the  lower  parts,  from  which  it  can  enter  the  trap  and 
be  discharged. 

A  return  trap,  in  addition  to  restricting  the  discharge,  must  effectively 
accomplish  the  following: 

1.  The  discharge  of  all  water  of  condensation  as  formed.     Otherwise 
water  accumulates  in  the  radiator,  prevents  free  discharge  of  air  and  thus 
reduces  the  amount  of  surface  effective  for  emitting  heat  from  the  steam. 

2.  The  discharge  of  all  air  and    other  gases  from  the  radiator  im- 
mediately upon  their  reaching  the  discharge  outlet. 

3.  Thorough  prevention  of  the  discharge  of  steam  to  the  return. 

To  accomplish  these  requirements  the  valve  of  a  return  trap  must 
open  or  close  within  a  very  narrow  range  of  temperature,  above  or  below 
that  of  steam  at  pressure,  irrespective  of  variations  in  steam  pressure, 
and  must  adapt  itself  to  such  changes  of  pressure  and  corresponding  steam 
temperature  as  may  be  met  in  practice. 

A  brief  review  of  the  various  types  of  return  traps  will  facilitate  a 
better  understanding  of  tests  and  the  results  which  are  desired. 

All  return  traps  commonly  used  in  low-pressure  or  vacuum  steam  heat- 
ing practice  may  be  classed  as  float,  differential,  and  thermostatic  traps. 

Float  traps  may  have  sealed  floats,  Figure 
14-2,  or  inverted  open  buckets  as  the  means  of 
operation.  In  either  case,  the  float  is  raised 
by  incoming  condensation  to  uncover  the  valve 
seat  through  which  water  is  discharged.  Air 
escapes  into  the  return  pipe  through  an  air 
port,  which  must  be  located  above  the  highest 
water  level  in  the  trap.  The  air  port  is  con- 
trolled in  some  makes  by  thermostatic  devices 
to  prevent  leakage  of  steam  to  the  return. 

Tests  upon  a  float  trap  may  generally  be 
expected  to  show  considerable  leakage  of  steam 
to  the  return  unless  the  air  port  is  thermo- 
Fig.i4-2  Float  trap  with  sealed  float     statically   controlled.     If  the   air  port  is  so 

154 


controlled,  the  small  port  and  its  mechanism  may  be  vulnerable  to  the  effects 
of  dirt  and  rust.  Such  traps,  however,  •will  be  found  to  have  large  water 
discharge  capacities  and  some  of  the  various  makes  can  be  used  to  advan- 
tage where  widely  varying  volumes  of  water  must  be  discharged  without 
respect  to  temperature. 

A  differential  trap  depends  for  operation  upon  the  difference  in  pres- 
sure at  the  inlet  and  at  the  outlet.  In  its  simplest  form,  it  is  a  check  valve 
which  is  closed  when  the  difference  in  the  pressures  ahead  and  back  of  the 
clapper  is  insufficient  to  overcome  the  weight  of  the  clapper,  Inasmuch  as 
no  special  means  are  provided  for  discharge  of  air,  such  a  valve  may  be  ex- 
pected to  leak  steam  to  the  return  under  any  conditions  of  higher  differential 
pressure,  and  to  stay  closed  with  consequent 
;iir  binding  and  water  logging  of  the  radia- 
tion when  the  pressure  differential  falls 
below  the  predetermined  limit  for  which  the 
valve  is  adjusted. 

Another  form  of  differential  trap  is 
shown  in  Figure  14-3.  Water  entering  the 
valve  body  raises  the  float,  thus  closing  the 
air  port  by  means  of  the  valve  piece  attached 
to  it.  A  higher  pressure  in  the  lower  part 
of  the  trap  B  than  that  existing  in  the 
chamber  A  results  in  the  operation  of  the 
piston  which  raises  the  valve  from  its  seat 
by  means  of  the  connecting  valve  stem.  As 
the  condensation  is  discharged,  the  water  Fi*-  V1;3-  pitivn-ntmi  trap 

,  ,  ,  „  „      ,  with  float  and  piston 

level  lowers  and  causes  the  float  to  tall,  thus 

uncovering  the  air  port,  and  equalizing  the  pressures  on  opposite  sides  of 
the  piston.  The  weight  of  the  operating  parts  and  the  force  of  the  spring 
then  closes  the  valve.  This  trap  may  be  expected  to  show  fairly  good 
results  in  laboratory  tests  but  it  is  not  satisfactory  under  the  usual  operating 
conditions  in  which  dirt  and  scale  are  always  present. 

A  thermostatic  trap  depends  for  its  operation  upon  the  difference  be- 
tween the  temperature  of  steam  at  the  pressure  in  radiator,  and  the  tempera- 
ture of  the  condensate  or  air  to  which  the  thermostatic  member  is  exposed. 

Many  devices  have  been  made  which  depend  upon  the  expansion  and 
contraction  of  metals  or  composition,  or  which  make  use  of  a  bourdon  tube. 
As  a  class  these  have  failed  because  there  is  not  enough  difference  in  area 
between  the  inside  and  outside  of  the  spring  to  produce  the  required  force 
at  normal  difference  in  temperature  between  steam  and  air  vapor  at  a  given 
exterior  pressure.  This  and  other  faults,  such  as  the  necessity  for  adjustment 
for  varying  pressure  conditions  and  slowness  in  operation,  have  led  to  the 
abandonment  of  these  types  by  most  manufacturers. 

Of  all  types  of  return  traps,  the  ones  in  general  use  today  are  those 
which  depend  for  movement  of  the  valve  piece  upon  the  change  of  vapor 
pressure  of  fluids  confined  within  a  flexible  chamber  when  subjected  to  dif- 
ferent exterior  pressures  and  temperatures.  The  volatile  fluids  contained  in 
the  flexible  chamber  vaporize  to  a  greater  or  less  pressure  depending  upon  the 

155 


temperature  of  the  steam,  vapor,  water  or  air  which  surround  the  chamber. 
The  expansion  or  contraction  of  the  chamber  moves  the  valve  piece  which 
is  attached  to  the  free  end  of  the  chamber. 

These  traps  are,  generally  speaking,  of  either  the  "inboard"  type  where 
the  thermostatic  member  is  exposed  to  the  temperature  and  pressure  of  the 
steam,  water  and  air  as  it  exists  at  the  radiator  outlet,  or  of  the  "outboard" 
type  which  depends  for  operation  upon  the  conditions  existing  between  the 
valve  piece  and  the  entrance  to  the  return  piping  beyond  the  trap. 

To  be  effective  for  the  inboard  type,  the  thermostatic  member  must 
expand  and  contract  through  a  distance  sufficient  to  open  and  close  the 
valve  under  the  influence  of  the  extremely  small  differences  of  temperature 
which  exist  during  normal  operation.  Most  traps  of  the  inboard  type  are 
inefficient  because  of  the  very  short  "stroke"  which  can  be  realized  with  the 
inelastic  disc  construction  generally  utilized  for  the  flexible  chamber,  this 
defect  resulting  in  inability  of  the  trap  to  rid  itself  of  dirt  and  scale. 

Traps  of  the  outboard  type  are  affected  by  the  pressure  and  temperature 
of  the  return.  They  are  in  proper  adjustment  only  at  one  definite  pressure 
and  temperature  and  out  of  adjustment  at  all  other  normal  combinations  of 
pressure  and  temperature.  They  cannot  be  adjusted  even  for  these  normal 
variations  in  radiator  pressures  and  vacuum  in  the  return,  and  as  a  result 
usually  water-log  and  air-bind  the  radiator  by  staying  closed  when  high 
temperature  and  pressure  exist,  or  stay  open  and  blow  steam  under  con- 
ditions of  low  temperature  and  pressure. 

The  trap  shown  in  Figure  14-4  is  a  ther- 
mostatic trap  of  the  inboard  type  and  as  such  is 
affected  in  operation  only  by  the  temperature 
and  pressures  existing  within  the  radiator.  The 
multifold  design  of  the  thermostatic  member  gives 
it  great  elasticity  and  consequent  ample  move- 
ment in  response  to  change  of  temperature  and 
pressure  in  the  medium  surrounding  it.  This 
member  contains  liquid  which  makes  the  trap 
self-compensating  for  difference  in  operating 
pressures  of  steam  within  the  radiator.  Its  con- 
struction, with  conical  valve  piece  seating  on 
sharp-edged  seat,  assures  positive  self -cleaning. 
Fig.  14-4.  The  Webster  Dirt  and  scale  cannot  lodge  between  valve  and 

Syiphon  Trap  sea^  an(j  pernu't  steam  to  leak  into  the  return. 

It  has  been  stated  that  a  trap  must  not  leak  steam  to  the  return,  but 
in  this  connection  there  should  be  no  confusion  between  steam  discharged 
through  a  trap  and  vapor  rising  from  hot  condensate.  Though  their  ap- 
pearance during  certain  forms  of  visual  tests  are  much  alike,  they  are  two 
entirely  different  things,  and  if  confused  with  each  other,  as  is  sometimes 
done,  wrong  conclusions  will  result. 

Many  times,  highly  efficient  radiator  traps  are  condemned  for  leaking 
steam,  due  to  the  observed  vapor  of  re-evaporation  noted  at  their  discharge 
outlet,  and  less  efficient  traps  have  been  commended  because  of  absence  of 
such  vapors. 

156 


noo 


Kig. 
perature 


(MARK!  AND    DAVIS) 
IF  LIQUID(/I)-|HEAT  OF  LIOU 


'/////////, 


y////////////////// 


UNO  INTERSECTION  OF  TERMINAL  PRESSURE  OR 
TEMPERATURE  VVITH  0^  VERTICAL  AND  FOLLOW 
UP  DIAGONAL  NORTH-EAST  TO  INTERSECTION  OF 
INITIAL  PRESSURE  OR  TEMPERATURE.  THIS  POINT 
READ  ON  HORIZONTAL  SCALE  OF  PER-CENTB  IS 
THE  RE-EVAPORATION  AT  (  -t  (OR  1',-JJ,) 


>.     Re-evaporation  chart  for  determining  the  percentage  of  water  re-evaporated  from  any  tem- 
between  300  nnd  170  deg.  fahr.  into  water  vapor  of  a  lower  temperature  and  corresponding  pressure 


157 


The  absence  of  vapor  at  the  discharge  is  in  reality  an  indication  that  the 
trap  is  holding  back  condensation  and  entrained  air  until  the  temperature 
of  the  discharge  is  materially  less  than  that  of  steam  at  the  pressure  of  the 
outlet.  The  consequence  of  such  holding  back  is  a  partially  air-bound  and 
water-logged  radiator,  with  less  than  full  radiating  efficiency. 

Visibility  is  deceptive.  A  great  amount  of  moisture  in  the  atmosphere 
and  favorable  light  conditions  both  add  to  the  visibility.  The  air  dis- 
charged from  an  efficient  trap  is  saturated  with  water  at  discharge  tempera- 
ture and  this  water  mixing  with  air  at  room  temperature  looks  like  steam, 
while  the  discharge  of  a  trap  utterly  deficient  in  air  removal  shows  only  the 
vapor  of  re-evaporation. 

The  water  of  condensation  contains  total  heat  in  excess  of  that  in  water 
of  condensation  at  lower  pressure.  This  excess  heat  boils  off  some  of  the 
condensation  into  steam.  The  amount  so  boiled  off  is  entirely  dependent 
on  excess  of  total  heat  in  outflowing  condensate  above  total  heat  of  water 
at  lower  pressure. 

If  steam  passes  out  with  condensate,  a  steam  of  greater  total  heat  is 
dissipated.  A  fully  efficient  trap  releases  the  condensation  at  or  near  steam 
temperature  and  radiator  pressure,  into  a  return  of  lower  pressure.  All 
heat  above  that  consistent  with  lower  pressure  then  generates  vapor.  This 
vapor  passes  to  the  vapor  receiver  in  a  test.  A  certain  amount  of  vapor 
per  pound  of  condensation  is  normal  and  any  excess  of  vapor  above  the 
normal  is  steam  leakage. 

The  condensate  from  a  higher  pressure  into  a  lower  pressure  will  never 
be  at  a  higher  temperature  than  that  due  to  steam  at  the  lower  pressure. 
The  excess  of  the  heat  in  the  outflowing  condensate  will  flash  part  of  the 
water  into  steam. 

These  points  are  emphasized  to  show  the  fallibility  of  visibility  test  to 
show  the  efficiency  of  return  traps. 

Very  rough  tests  are  often  made  by  connecting  a  trap  to  the  end  of  a 
pipe  or  to  outlets  in  a  header  to  which  steam  is  admitted  at  the  pressure 
usually  used,  the  trap  discharging  into  the  atmosphere.  A  test  of  this  kind 
merely  shows  whether  the  trap  shuts  off. 

Comparative  values  are  sometimes  placed  upon  traps  by  considering 
the  quantity  of  water  discharged  during  equal  periods  of  time.  The  traps 
are  successively  attached  to  the  same  test  radiator,  the  condensate  is  care- 
fully weighed  and  the  conclusion  drawn  that  the  trap  passing  the  largest 
quantity  in  a  given  time  is  the  best.  It  is  evident  that  such  a  test  shows 
merely  the  condensing  rate  of  the  radiator  under  the  room  temperature 
conditions.  Nothing  is  demonstrated  regarding  the  performance  of  the  trap, 
for  it  is  only  when  condensation  is  held  back  in  the  radiator  that  the  capacity 
of  the  trap  is  exceeded.  This  test  is  only  a  determination  of  the  condensate- 
discharging  capacity  of  the  trap. 

The  vacuum  which  can  be  maintained  at  the  discharge  end  of  a  trap  is 
occasionally  regarded  as  a  criterion  of  the  comparative  worth  of  traps.  For 
such  tests,  the  apparatus  consists  of  a  radiator,  a  return  trap,  a  return 
connection  to  a  vacuum  pump,  and  devices  for  maintaining  constant  pressure 
of  steam  supply  to  the  radiator  and  for  operating  the  pump  at  a  constant 

158 


speed.  The  trap  maintaining  the  highest  vacuum  during  the  test  is  consid- 
ered to  be  the  best.  With  little  or  no  attempt  to  determine  the  extent  to 
which  the  radiator  is  air  and  water  bound,  such  data  has  frequently  led  to  a 
wrong  choice  of  traps  and  the  results  when  in  actual  operation  on  a  heating 
system  have  proved  correspondingly  unsatisfactory. 

Another  test  is  to  connect  a  trap  to  a  radiator  with  discharge  to  atmos- 
phere, and  noting  the  operation. 

Particularly  erroneous  conclusions  will  be  reached  unless  careful 
distinction  is  made  between  the  vapor  which  is  steam  and  the  vapor  which 
is  due  to  re-evaporation. 

Much  can  be  learned  as  to  trap  behavior  from  such  a  test,  yet  the 
conditions  are  often  not  the  same  as  in  actual  service  operation.  The  return 
piping  connection  and  the  pressure  therein  have  considerable  effect  upon 
their  operation  so  that  rough  tests  of  this  nature  should  not  be  accepted  as 
conclusive,  but  as  indicative  of  trap  operation. 

These  few  devices  and  methods  are  the  ones  commonly  used  for  de- 
termining comparative  worth  of  return  traps  where  only  the  most  easily 
procurable  testing  apparatus  is  available.  Like  other  scientific  investiga- 
tions more  careful  methods  will  lead  to  more  reliable  results  and  with  proper 
apparatus  and  thoughtful  procedure  it  is  entirely  practicable  to  obtain  test 
data  which  can  be  relied  upon  as  accurately  forecasting  the  success  which 
may  be  expected  from  the  use  of  any  return  trap  in  an  actual  heating  system. 

The  first  thought  for  any  reliable  test  should  be  to  create  laboratory 
conditions  as  nearly  as  possible  like  those  met  in  actual  practice.  Coinci- 
dently,  the  apparatus  should  be  designed  to  provide  exactly  like  and 
simultaneous  test  conditions  where  traps  are  tested  for  comparison,  and  of 
course,  appliances  for  measuring  the  results  must  be  carefully  placed  and 
adjusted.  Then,  by  following  a  proper  test,  planned  to  exhaust  the  various 
possibilities  of  different  operating  conditions,  results  are  secured  which  can 
be  accepted  as  conclusive. 

Enough  has  been  said  to  show  that  valuable  data  regarding  the  probable 
performance  of  return  traps  can  be  obtained  in  the  laboratory  where  suitable 
apparatus  is  available  and  where  suitable  test  methods  are  carefully  applied. 
However,  the  long-time  test  of  devices  in  actual  heating  systems  is  the  best 
guide  for  determining  the  relative  value  of  return  traps,  and  further,  the 
efficiency  of  a  good  return  trap  can  be  fully  realized  only  when  the  heating 
system  itself  is  properly  planned  and  operated. 


159 


Part  II.  Webster  System  Specialties 
and  Applications* 


CHAPTER  XV 

Webster  Systems  of  Steam  Heating 

THE  title  "Webster  Systems  of  Steam  Heating"  is  used  to  designate 
not  only  the  Webster  Specialties  which  are  used  in  the  several  types  of 
heating  systems,  but  also  the  methods  and  arrangements,  most  of  them 
original   with   the   manufacturer,   which   assure  economical   and   efficient 
operation  of  the  heating  plant  as  a  whole. 

In  addition  this  designation  embraces  a  far-reaching  policy  of  co-opera- 
tion— Webster  Service — which  is  rendered  through  branch  offices  and  service 
centres  of  the  manufacturer  in  the  principal  cities. 

This  three-fold  system  of  specialties,  methods  and  service  is  the 
result  of  continuous  development  since  1888. 

Many  of  the  methods  of  application  have  been  reduced  to  the  form  of 
Standard  Service  Details,  as  shown  in  Chapter  22  and  elsewhere  in  this  book. 

The  selection  and  adoption  of  a  Webster  System  carries  with  it  the 
assurance  to  the  architect,  to  the  designing  engineer,  to  the  heating  con- 
tractor and  to  the  owner,  that  the  responsibility  is  not  divided  between 
manufacturers  of  various  appliances. 

In  a  Webster  System  all  of  the  appliances  are  co-ordinated  in  their 
application  and  function,  and  the  great  risk  of  patchwork  selection  and 
responsibility  is  avoided. 

Webster  Specialties  have  been  proved  by  the  test  of  use  over  many  years 
to  be  the  highest  quality  attainable  in  design,  workmanship  and  material. 

Webster  Service  and  the  standard  and  special  details  of  recommended 
application  are  the  result  of  long  experience  and  pioneering  in  solving  the 
practical  problems  that  have  arisen. 

Webster  Systems  are  flexible.  There  is  a  type  or  a  modification  that 
will  fit  each  building.  Following  the  classification  in  Chapter  10,  Webster 
Systems  of  Steam  Heating  are  divided  into  two  general  types:  Webster 
Modulation  Systems  and  Webster  Vacuum  Systems. 

Webster  Modulation  Systems 

As  stated  in  Chapter  10,  the  vacuum  and  modulation  types  of  steam 
heating  systems  are  sufficiently  alike  to  be  classed  as  one  broad  type  of 
system,  in  which  the  circulation  of  steam  is  produced  by  a  flow  of  the  heating 

'Drawings  showing  applications,  and  dimensions  of  apparatus  are  subject  to  change  without  notice. 
CertiBed  drawings  of  apparatus  will  be  furnished  upon  request. 


161 


medium  from  a  higher  to  a  lower  pressure.  They  are  dissimilar  in  the  method 
of  disposing  of  the  products  of  condensation. 

The  Modulation  System  may  be  sub-divided  according  to  source  of 
steam  supply,  or  more  particularly  type  of  boiler,  into  three  general  classes: 

1.  Low-pressure  heating  boilers  operating  up  to  10-lb.  pressure. 

2.  Boilers  operating  at  from  10  to  50-lb.  pressure. 

3.  Street  systems,  carrying  any  pressure. 

1.  BOILERS  OPERATING  UP  TO  10-LB.  PRESSURE:  A  typical  arrange- 
ment of  the  Webster  Modulation  System  as  installed  in  connection  with  a 
low-pressure  heating  boiler  is  shown  in  Figure  15-1.  The  initial  pressure 
is  closely  controlled  by  means  of  an  extremely  sensitive  Webster  Damper 
Regulator.  The  steam  is  admitted  to  each  radiator  through  a  Webster 
Modulation  Valve  which  permits  modulation  of  room  temperature  by  simple 
hand  manipulation.  Condensation  is  discharged  and  air  is  vented  from 
each  radiator  through  a  Webster  Return  Trap  which  maintains  full  heating 
efficiency  of  the  radiator  and  eliminates  the  annoyance,  difficulties  and 
noises  common  to  ordinary  gravity  steam  heating  systems. 

Condensation  and  air  from  each  radiator  flow  by  gravity  through  a 
system  of  return  risers  and  mains  into  the  Webster  Modulation  Vent  Trap, 
where  the  air  is  automatically  vented,  permitting  the  system  under  favor- 
able boiler  conditions  to  operate  for  long  periods  under  partial  vacuum  or 
"vapor,"  but  also  due  to  the  flexibility  of  the  system  permitting  higher 
pressures  to  be  carried  in  severe  weather  when  a  maximum  amount  of  heat 
is  required.  Fig.  24-61,  Page  268,  shows  the  detail  connections  of  the  Modu- 
lation Vent  Trap. 

The  system  of  supply  and  return  mains  and  risers  should  be  sized  and 
run  as  recommended  for  Modulation  Systems  in  Chapter  11.  As  a  general 
rule,  supply  mains  and  risers  are  not  dripped  through  traps,  but  directly 
into  a  wet -return  line,  the  air  being  vented  into  the  dry-return  line  which 
is  run  back  above  the  boiler  water  line  to  the  Modulation  Vent  Trap. 

Where  building  conditions  make  the  running  of  a  wet -return  line  im- 
possible, the  mains  and  supply  risers  are  dripped  and  vented  through 
Webster  Return  Traps  into  the  dry -return  line.  It  has  however  been  found 
preferable  from  practical  experience  to  run  a  wet-return  line  wherever 
it  is  physically  possible  to  do  so. 

In  view  of  the  general  adoption  of  Webster  Modulation  Valves  and  the 
hot-water  types  of  radiators,  the  top  feed  supply  connections  are  more 
generally  used.  When  placed  in  this  position,  the  valves  are  in  a  very  accessible 
location  and  it  will  be  found  easier  to  control  the  temperature  of  the  room 
by  operating  the  valve  than  by  following  the  customary  method  of  opening 
and  closing  the  window. 

Figure  22-43  on  page  228  illustrates  the  method  of  dripping  and  venting 
the  supply  main  into  the  wet  return.  Figures  22-45  and  22-49  on  pages  229 
and  232  show  how  the  basement  radiators  are  connected  up  to  the  system. 
Several  methods  of  dripping  the  risers  and  mains  through  Return  Traps 
into  the  dry  return  are  shown  in  Chapter  22  on  pages  215,  216  and  217. 

The  Wrebster  Modulation  Vent  Trap  is  essentially  a  part  of  the  Webster 
Modulation  System,  to  be  used  on  installations  where  the  sizes  of  pipes, 

162 


valves  and  return  traps  have  been  computed  in  accordance  with  the  methods 
explained  in  Chapter  1 1  and  also  on  the  basis  of  pressure  differential  outlined 
in  Chapter  23,  and  summarized  in  Table  23-7. 

Where  the  pressure  difference  between  that  in  the  boiler  and  that  in 
the  main  return  line  is  likely  to  exceed  the  available  gravity  head  between 
the  return  main  and  the  boiler,  the  Webster  High-duty  Vent  Trap  may  be 
required. 

The  principal  conditions  under  which  the  High-duty  Vent  Trap  may 
be  employed  are  as  follows: 

1.  Where  it  is  of  advantage  to  design  the  system  for  a  continuous 
operating  steam  pressure  ranging  from  2  to  3  Ib.  to  occasionally  10  Ib. 

2.  In  an  existing  installation,  where  the  pipe  sizes  are  already  fixed, 
as  for  example  an  old  building  in  which  complete  steam  circulation  cannot 
be  obtained  under  2  or  3  Ib. 

3.  In  a  proposed  installation  where  the  basis  upon  which  the  pipe  sizes, 
valves  and  return  traps  are  figured  is  either  uncertain  or  unknown. 

4.  Under  certain  operating  conditions  such  as  continually  changing 
janitor  service,  operating  the  boiler  without  the  use  of  a  sensitive  low-pressure 
damper  regulator  or  with  the  damper  regulator  entirely  detached. 

5.  In  cases  where  special  grades  of  bituminous  coal  are  burned  in 
certain  types  of  boilers,  and  it  is  impossible  to  maintain  low  steam  pressure 
even  with  careful  attention  and  correct  damper  regulation. 

2.  BOILER  PRESSURE  FROM  10  TO  50  LB.:  With  this  type  of  system 
the  heating  medium  is  generally  live  steam  taken  directly  from  the  boiler 
and  is  reduced  to  the  desired  pressure,  varying  from  atmospheric  up  to  1  or 
2  Ib.,  by  means  of  a  pressure-reducing  valve.  This  initial  pressure  in  the 
heating  main  will  vary  according  to  the  pressure  drop  for  which  the  supply 
piping  has  been  sized,  and  to  a  certain  extent  with  respect  to  the  outside 
-  temperature  and  weather  conditions. 

The  only  exhaust  steam  available  is  that  from  boiler-feed  pumps  and 
other  auxiliaries  if  steam-driven.  The  exhaust  is  utilized  after  it  has  been 
made  suitable  for  use  by  passing  through  a  Webster  Oil  Separator,  drained 
by  a  Webster  Grease  Trap. 

The  system  of  supply  and  return  mains  and  risers  should  be  sized  and 
run  as  recommended  for  Case  1. 

In  small  and  moderate  size  buildings  the  supply  mains  are  usually  run 
on  the  basement  ceiling  and  connected  through  laterals  to  up-feed  risers 
supplying  the  radiators. 

In  tall  buildings  and  in  buildings  of  certain  types  it  is  desirable  to  avoid 
running  the  large  supply  mains  on  the  basement  ceilings.  Where  a  building 
is  spread  over  a  large  area,  if  the  supply  main  is  located  on  the  basement 
ceiling,  the  pitch  required  by  the  main  and  by  the  dry  return  may  cause  the 
latter  to  be  too  low  when  approaching  the  point  of  discharge.  In  both  of 
these  cases,  what  is  known  as  the  "overhead"  or  down-feed  system  is  em- 
ployed, the  steam  being  fed  through  a  main  up-feed  riser  to  a  distributing 
main  located  at  the  ceiling  of  the  top  story  or  preferably  in  the  attic,  steam 
being  delivered  to  the  various  radiators  through  a  series  of  down-feed  risers. 

The  drop  risers  are  connected  into  a  wet  return  or  gravity  drip  line. 


The  return  risers  are  joined  into  an  overhead  dry-return  main,  which  is 
carried  back  to  the  point  of  discharge.  The  main  supply  riser  is  dripped 
either  into  the  wet  return  or  through  a  Webster  Heavy-duty  Trap  or  suitable 
size  return  trap  into  the  dry-return  main. 

In  buildings  of  only  one  story,  the  steam  supply  line  is  run  along  the 
ceiling  to  feed  each  radiator  through  a  short  down-feed  riser  which  must 
be  dripped  through  a  return  trap  into  a  dry  return.  The  use  of  the  Webster 
Double-service  Valve  attached  to  the  radiator  as  shown  in  Fig.  24-23,  page 
253,  performs  the  two-fold  service  of  supply  valve  for  the  radiator  and  a 
trap  for  draining  the  riser. 

For  factories,  stores,  loft  buildings,  etc.,  when  there  are  a  number  of 
radiators  heating  one  large  room,  Webster  Modulation  Valves  are  sometimes 
omitted  and  ordinary  radiator  supply  valves  used  instead.  Such  systems 
are  designated  as  Webster  Semi-Modulation  Systems  to  distinguish  them 
from  the  usual  type  of  modulation  system. 

In  general,  for  the  type  of  building  for  which  the  Webster  Modulation 
System  is  proper,  the  advantage  of  using  Webster  Modulation  Valves  is  so 
evident  that  they  are  considered  a  necessary  part  of  the  equipment. 

Radiators  may  be  exposed,  concealed  under  window  seats  or  behind 
grilles,  or  placed  overhead  to  take  care  of  skylights  and  unusual  roof  ex- 
posures, as  with  vacuum  systems. 

The  radiators  are  drained  through  Webster  Return  Traps,  into  a  system 
of  return  risers,  and  in  the  same  manner. 

Air-valves  are  unnecessary  on  the  radiators,  as  the  air  is  relieved  through 
the  return  traps. 

It  should  be  noted,  however,  that  as  the  actual  difference  in  pressure 
through  the  supply  valve  and  return  trap  of  a  modulation  system  is  less 
than  with  a  vacuum  system,  these  valves  and  traps  must  not  be  rated  as 
high  for  modulation  as  for  vacuum  system  practice.  It  will  therefore  be 
observed,  from  a  study  of  Chapter  11,  that  it  is  necessary  to  deduct  the 
pressure  drop  for  which  the  system  is  designed  from  the  initial  pressure  in 
the  heating  main.  With  atmospheric  pressure  in  the  return  piping,  this 
difference  will  represent  the  differential  pressure  on  which  the  capacity  rating 
of  the  valves  and  traps  should  be  based. 

The  products  of  condensation  flow  by  gravity  through  the  system  of 
return  risers  into  the  basement  return  main,  thence  to  a  hot-well  or  to  the 
receiver  of  a  pump  and  receiver.  If  the  former,  a  condensation  pump  is 
used  to  discharge  the  water  into  the  boiler.  In  the  latter  case,  the  pump 
and  receiver  take  care  of  the  liberation  of  entrained  air  and  return  of 
condensation  to  the  boiler. 

The  condensation  pump,  or  pump  and  receiver,  will  usually  be  electric- 
ally driven,  but  if  the  boiler  pressure  is  25  or  30-lb.  or  above,  the  steam- 
driven  type  may  be  used. 

3.  STREET  SYSTEM  CARRYING  ANY  PRESSURE:  Where  street  steam 
service  is  maintained,  the  modulation  system  is  similar  in  most  respects 
to  either  Case  1  or  2  described  above,  except  that  no  provision  is  made  for 
returning  the  condensation  to  the  boiler  by  a  modulation  vent  trap,  as  in  the 
case  of  a  low-pressure  heating  boiler,  or  by  some  form  of  return  pump  where 

164 


higher  pressures  are  carried  on  the  boiler.  The  water  of  condensation  is 
usually  discharged  to  the  sewer  through  a  meter  in  the  return  line,  except 
where  a  flat  rate  per  square  foot  of  radiation  is  charged  in  which  case  no 
meters  are  used. 

Where  exhaust  steam  at  1  or  2-lb.  pressure  is  supplied  by  the  street 
service,  a  connection  is  made  directly  from  the  main  to  the  supply 
piping  in  the  building.  If  steam  at  higher  pressures  is  furnished,  a  pressure- 
reducing  valve  is  placed  between  the  service  connections  and  the  main 
heating  pipe,  to  regulate  the  steam  to  any  desired  initial  pressure  on  the 
system.  By  this  means  the  pressure  may  be  controlled  to  best  suit  outside 
temperature  and  weather  conditions. 

Webster  Vacuum  Systems 

Webster  Vacuum  Systems  may  be  sub-divided  into  four  classes,  accord- 
ing to  the  source  of  steam  supply: 

1.  High-pressure  or  power  boilers,  with  exhaust  steam  available  from 
engines  and  auxiliaries. 

2.  Medium-pressure  boilers,  15  to  50-lb.  pressure. 

3.  Low-pressure  boilers  up  to  15-lb.  pressure. 

4.  Street  systems. 

1.  WEBSTER  VACUUM  SYSTEM  WITH  POWER  BOILERS:  With  this 
type  of  vacuum  system  the  source  of  steam  supply  may  be 

(A)  Exhaust  steam  from  the  engine;  or 

(B)  Exhaust  steam  from  engines  or  auxiliaries,  supplemented  by 
live  steam  at  reduced  pressure. 

In  the  Case  A  when  the  power  load  exceeds  the  heating  load,  the  supply 
of  exhaust  steam  will  be  ample  for  the  requirements  of  the  heating  system 
and  in  addition  may  also  be  used  in  a  Webster  Feed-water  Heater  to  preheat 
the  water  supplied  to  the  boilers.  Under  such  conditions  the  heating  plant 
is  exceedingly  economical  since  it  utilizes  a  by-product,  exhaust  steam, 
which  otherwise  might  be  wasted. 

It  is  under  such  conditions  that  the  Webster  Vacuum  System  is  most 
advantageous  since  it  ensures  a  rapid  circulation  of  steam  through  the 
entire  heating  system  with  a  minimum  back  pressure  on  the  engine.  The 
reduction  in  back  pressure  saves  in  the  steam  consumption  of  the  engines. 

In  the  Case  B  where  the  quantity  of  available  exhaust  steam  is  not  suffi- 
cient, live  steam  at  reduced  pressure  is  automatically  admitted  into  the 
heating  main  to  make  up  the  deficiency.  In  this  design  of  heating  plant, 
care  should  be  exercised  to  see  that  all  of  the  exhaust  steam  is  utilized, 
including  that  from  the  various  pumps  and  auxiliaries. 

Fig.  15-2  illustrates  a  conventional  layout  in  elevation,  of  a  Webster 
Vacuum  System,  using  both  exhaust  and  live  steam  in  combination  with 
a  Webster  Feed-water  Heater. 

Referring  to  the  illustration,  the  exhaust  steam  is  made  suitable  for 
efficient  heating  and  for  subsequent  use,  when  condensed,  by  passing 
through  a  Wrebster  Oil  Separator,  which  must  be  properly  dripped. 

It  is  very  important  that  the  oil  separator  shall  be  properly  dripped. 

165 


For  ordinary  cases,  where  the  pressure  in  the  exhaust  main  is  maintained 
above  that  of  the  atmosphere,  the  Webster  Grease  Trap,  also  shown  in  the 
illustration,  is  highly  efficient.  A  daily  inspection  of  the  grease  trap 
should  be  made  while  the  plant  is  in  use,  to  be  sure  that  it  is  operating 
properly.  In  systems  which  lie  idle  for  a  portion  of  the  year,  a  careful 
examination  should  be  made  on  starting  up,  to  see  that  the  grease  trap  and 
the  pipe  connections  thereto  have  not  become  clogged  on  account  of  the 
solidification  of  the  grease  during  the  period  of  such  idleness.  Failure 
of  the  trap  to  function  properly  will  cause  the  separated  oil  to  be  carried 
over  into  the  heating  system  and  eventually  to  reach  the  boilers,  where  it  is 
very  likely  to  produce  bagging  or  blistering  of  the  shell  plates  and  tubes. 

If  the  partial  vacuum  created  by  the  vacuum  pump  extends  into  the 
heating  mains,  at  times  when  the  supply  of  exhaust  steam  is  insufficient, 
and  it  is  not  supplemented  by  live  steam,  it  will  be  necessary  to  drain  the 
oil  separator  in  a  special  manner.  Figs.  24-27  and  24-28  in  Chapter  24 
show  both  methods  of  draining  the  oil  separator. 

The  necessary  live  steam  is  admitted  through  a  pressure-reducing 
valve  of  a  suitable  size  and  type.  A  Webster  Water  Accumulator  is  used, 
as  shown  in  the  illustration,  to  ensure  proper  functioning  of  the  valve. 
The  addition  of  a  pop  safety  valve  in  the  low-pressure  main,  set  to  blow 
at  a  few  pounds  above  the  normal  working  pressure,  will  give  warning  of 
any  tendency  of  the  reducing  valve  to  build  up  pressure  during  periods 
when  the  demand  for  steam  is  very  light. 

Dripping  Supply  Mains  and  Risers:  Supply  and  return  mains  and 
risers  should  be  sized  and  run  as  recommended  for  vacuum  system  practice 
in  Chapter  11.  The  method  of  dripping  mains  and  risers  into  the  vacuum 
return  line  varies  with  the  local  conditions  of  each  building.  In  the  typical 
illustration  the  base  or  "heel"  of  the  main  supply  riser  is  shown  dripped 
through  a  Webster  Heavy-duty  Trap,  protected  from  scale  and  sediment 
by  a  WTebster  Dirt  Strainer. 

A  few  general  suggestions  regarding  the  dripping  of  supply  mains  and 
risers  will  be  helpful  and  will  assist  in  determining  which  of  the  several 
methods  of  application  will  be  followed. 

As  stated  in  the  description  of  modulation  systems,  the  overhead  or 
down-feed  system  of  supply  piping  is  employed  in  tall  buildings  and  in 
buildings  of  certain  types  where  it  is  desirable  to  avoid  the  running  of  large 
supply  mains  in  the  basement.  Steam  is  conveyed  through  a  main  up-feed 
riser  to  a  distributing  main  located  either  on  the  ceiling  of  the  top  story  or 
in  the  attic  space  above.  The  space  should  have  sufficient  head  room  to 
give  easy  access  to  the  valves  which  are  generally  placed  in  the  run-outs 
from  the  main  to  the  riser,  and  also  to  permit  future  repairs.  It  is  needless  to 
say  that  either  the  attic  floor  should  be  made  strong  enough  to  carry  the 
weight  of  a  man  or  a  narrow  platform  should  be  provided.  Either  can  be 
made  of  two  2-in.  thick,  hard  pine  planks  of  24-in.  total  width  and  sus- 
pended by  iron  hangers  fastened  to  the  roof  framing  and  spaced  at  regular 
intervals.  The  platform  should  run  parallel  to  pipe  lines  and  close  enough 
to  allow  a  man  suitable  space  for  working. 

The  main  riser  is  dripped   through  a  Webster  Heavy-duty  Trap  and 

167 


\Vebster  Dirt  Strainer,  as  shown  in  Figure  22-2.  The  drop  risers  are  in- 
dividually dripped  through  Webster  Return  Traps,  with  proper  provision 
for  cooling  surface  between  the  point  of  drainage  and  the  trap,  the  sur- 
face being  arranged  either  horizontally  or  vertically,  as  space  conditions 
may  determine.  As  dirt  and  scale  are  more  apt  to  accumulate  at  such  drip 
points  than  elsewhere  in  the  piping  system,  it  is  essential  also  that  the  traps 
be  protected  by  means  of  dirt  pockets  made  up  of  pipe  and  fittings,  as 
shown  in  Figs.  22-7  and  22-8,  or  by  means  of  Webster  Dirt  Strainers, 
shown  in  Fig.  22-10.  The  latter  are  simple,  self-contained  fittings,  easy  to 
install,  and  convenient  and  readily  accessible.  The  cleaning  of  these  points 
where  dirt  accumulates  is  essential  to  the  success  of  the  heating  system. 

Another  method  of  dripping  the  drop  risers  of  down-feed  systems, 
which  is  very  satisfactory  where  building  conditions  permit  its  use,  is  to 
connect  all  of  these  risers  into  a  wet -return  or  gravity  drip  line.  This 
necessitates  the  running  of  a  separate  wet-return  line  in  the  basement 
along  the  floor.  In  such  case,  return  traps  are  not  needed  for  dripping  the 
risers,  but  each  riser  must  connect  to  the  gravity  drip  line  through  a  hori- 
zontal line  in  which  an  efficient  check  valve  is  placed.  Various  methods  of 
accomplishing  this  are  shown  in  Figs.  22-28,  22-29  and  22-30  in  Chapter  22. 

Where  building  conditions  justify  the  running  of  a  basement  supply 
main,  with  a  series  of  up-feed  risers,  each  riser  is  dripped  through  a  Webster 
Return  Trap,  protected  by  a  dirt  pocket  or  Webster  Dirt  Strainer,  into 
the  vacuum  return  line.  The  main  itself  is  dripped  at  various  points 
where  it  rises  or  where  its  size  is  reduced,  so  as  to  relieve  the  condensation 
and  air  which  would  otherwise  accumulate  and  interfere  with  the  proper 
circulation  of  steam.  These  points  are  also  dripped  through  Webster 
Return  Traps,  properly  protected  from  dirt  and  sediment.  Provision  for 
cooling  surfaces  in  the  pipe  connection  to  the  return  trap  is  of  prime  impor- 
tance with  this  method  of  dripping.  (See  Figs.  22-31,  22-32  and  22-33.) 

Very  tall  buildings  sometimes  require  a  combination  of  the  up-feed 
and  down-feed  system  of  supply,  with  a  combination  of  the  various  methods 
of  dripping. 

The  drip  at  the  base  of  a  main  up-feed  riser  is  commonly  referred  to 
as  a  "main  riser  drip"  or  "drip  at  heel  of  main  riser."  Drips  at  the  bottom 
of  up-feed  or  down-feed  risers  where  traps  are  used  are  called  "supply  riser 
drips."  Drips  at  various  points  on  the  basement  main  are  called  "main 
drips."  Wet -return  lines  are  called  "gravity  drips." 

Supply  lines  to  fan  heater  coils,  hot-water  generators,  etc.,  usually 
require  separate  drips,  using  either  Webster  Heavy-duty  Traps  or  Webster 
Return  Traps,  depending  upon  the  volume  of  condensation  to  be  handled. 
Where  such  drips  are  to  be  taken  into  the  vacuum  return  line  comparatively 
close  to  the  vacuum  pump,  special  provision  must  be  made  on  account  of 
the  relatively  high  temperature  of  the  condensation. 

Supply  lines  to  apparatus  requiring  steam  at  pressure  above  15-lb., 
known  as  medium  or  high-pressure  lines  according  to  the  pressure  carried, 
should  not  be  dripped  directly  into  the  vacuum  return  line.  Special  methods 
of  taking  care  of  such  drip  points  must  be  followed.  Figure  20-2,  Page  203 
shows  one  method. 

168 


Radiator  Connections:  Regardless  of  the  arrangement  of  the  supply 
mains  and  risers,  and  the  methods  of  dripping  them,  the  supply  connections 
to  the  individual  radiators  will  be  similar,  as  shown  in  Figures  22-14,  22-15 
and  22-19. 

Horizontal  connections,  known  as  "laterals,"  are  taken  from  the 
supply  riser  to  the  radiator.  In  the  case  of  radiators  with  top-feed  connection, 
a  vertical  supply  line  will  be  taken  from  the  lateral  to  the  radiator  supply 
valve.  This  applies  particularly  to  radiators  of  the  hot -water  type,  in  which 
the  radiator  sections  are  connected  together  at  the  top  by  means  of  close 
nipples.  Sometimes  steam  radiators  may  be  similarly  fed,  using  the  first 
section  to  convey  the  steam  in  a  downward  direction,  particularly  where  a 
fractional-control  or  modulation  valve  is  used  with  this  type  of  radiator. 

In  Chapter  12  special  attention  is  called  to  the  necessity  for  proper 
sizing  and  grading  of  these  laterals. 

In  Figure  15-2  the  cast-iron  column  radiation  is  shown  supplied 
through  a  Webster  Modulation  Valve,  while  the  heating  coil  is  supplied 
through  an  ordinary  gate  valve. 

The  advantage  of  the  Webster  Modulation  Valve  is  that  it  provides  a 
convenient,  positive  means  of  throttling  the  steam  supply  to  each  radiator 
so  that  the  occupant  of  each  compartment  may  maintain  the  temperature 
which  he  desires,  without  regard  for  the  temperature  in  any  other  compart- 
ment. This  results  not  only  in  increased  comfort  to  the  occupant,  but  in 
decrease  of  the  amount  of  steam  used,  as  the  room  temperature  is  varied 
by  manipulation  of  a  single  valve  on  each  radiator,  and  not  by  opening  and 
closing  windows.  This  latter  method  is  the  customary  and  inefficient  way 
of  varying  room  temperature  where  ordinary  supply  valves  are  used,  owing 
to  the  inconvenience  and  uncertainty  of  such  valves  in  throttling  the  sup- 
ply of  steam. 

The  Webster  Modulation  Valve,  described  and  illustrated  in  detail 
in  another  chapter,  is  especially  designed  to  give  perfect  modulation  of 
room  temperature  with  less  than  a  full  turn  of  the  indicator,  the  position  of 
the  indicator  on  the  dial  showing  the  degree  of  opening.  Further,  during 
the  period  of  initial  warming-up  of  a  cold  room,  it  acts  as  a  quick-opening 
valve  and  where  the  proper  sizes  are  selected  for  the  operating  conditions, 
the  radiator  will  be  heated  all  over  in  20  minutes,  after  which,  if  the  weather 
conditions  are  such  that  a  smaller  volume  of  steam  is  required  to  maintain 
the  room  temperature,  the  indicator  is  turned  back,  and  steam  is  conserved. 

Radiators  may  be  placed  in  exposed  locations  beneath  windows  or 
between  columns,  as  shown  in  Figure  15-2,  or  may  be  wholly  or  partially 
concealed  under  window  seats  or  behind  grilles  (Figs.  6-14  and  6-15);  or  may 
be  located  overhead  as  with  skylight  coils  (Fig.  5-2). 

Each  of  these  conditions  requires  special  arrangement  of  supply  con- 
nections and  fixtures.  Some  helpful  suggestions  to  meet  particular  connec- 
tions may  be  found  by  studying  Webster  Service  Details  in  Chapter  22. 

Whether  to  employ  Webster  Modulation  Valves  or  ordinary  radiator 
supply  valves  is  optional  with  the  architect  or  designing  engineer  who 
selects  the  equipment.  The  modulation  type  is  recommended  wherever 
efficiency  and  economy  of  operation  are  desired,  as  the  additional  first 
cost  of  installation  is  very  little,  and  repairs  and  upkeep  are  negligible. 

169 


They  are  especially  to  be  recommended  in  hotels,  apartment  houses, 
and  other  buildings  with  transient  occupants  who  have  no  incentive  to 
economize  in  the  use  of  steam  where  ordinary  valves  are  used.  Also  greater 
economy  may  thus  be  secured  in  dormitories,  schools,  institutions,  etc., 
where  the  manipulation  of  the  radiator  valves  is  under  control  of  a  regular 
attendant  rather  than  the  occupant  of  the  room.  For  such  cases,  a  lock- 
shield  type  of  Webster  Modulation  Valve  with  key  is  frequently  used. 

The  Webster  Vacuum  System  is  admirably  adapted  for  use  where 
special  systems  of  automatic  temperature  control  are  used,  as  in  large  office 
buildings,  hotels,  etc.,  to  control  individual  room  temperatures. 

Disposal  of  the  Products  of  Condensation:  The  air,  gases  and  water 
comprising  the  products  of  condensation  of  steam  within  the  radiators, 
are  drained  from  each  radiator  by  a  Webster  Return  Trap  connected  at 
the  return  end.  Lateral  "run-outs"  conduct  this  condensation  to  a  series 
of  return  risers  which  convey  it  to  a  system  of  basement  return  mains, 
in  which  a  partial  degree  of  vacuum  is  maintained  by  a  steam  or  electrically 
driven  vacuum  pump,  according  to  conditions. 

The  Webster  Return  Trap  serves  the  triple  function  of  relieving  the 
air  and  gases  as  well  as  the  water  of  condensation  and  also  preventing  the 
escape  or  loss  of  steam  into  the  return  line. 

Air  valves  are  unnecessary.  Their  annoyances  and  discomforts  are 
entirely  eliminated. 

The  several  types  of  Webster  Return  Traps  and  the  various  methods 
of  application  for  different  conditions  are  explained  in  other  chapters. 

As  with  laterals  from  supply  risers,  return  run-outs  to  risers  must  be 
properly  sized  and  graded.  This  is  a  detail  which  often  requires  personal 
inspection  during  the  progress  of  the  installation,  particularly  where  the 
laterals  and  run-outs  are  run  in  pipe  or  sheet-metal  sleeves  which  in  turn  are 
embedded  in  concrete  or  other  solid  floors. 

The  Vacuum  Pump:  The  vacuum  pump  and  its  auxiliary  equipment 
may  be  referred  to  as  the  heart  and  lungs  of  a  vacuum  system.  It  is  all- 
important  that  they  be  properly  selected  and  sized,  and  that  the  function 
of  all  parts  of  this  equipment  be  thoroughly  understood  so  that  the  piping 
connections  will  be  properly  made.  (See  Chapter  13.) 

Various  types  and  arrangements  of  equipment  are  necessary  to  meet 
different  conditions. 

In  the  type  of  vacuum  system  which  is  now  being  described,  the  vacuum 
pump  will  usually  be  of  the  steam-driven  reciprocating  type,  steam  being 
furnished  directly  from  boilers  at  relatively  high  pressure. 

The  supply  of  steam  to  the  pump  is  automatically  controlled  by  a 
Webster  Vacuum-pump  Governor  actuated  by  the  degree  of  vacuum 
existing  in  the  vacuum  return  line  and  adjusted  to  stop  or  slow  down  the 
operation  of  the  pump  as  the  vacuum  approaches  the  point  for  which  the 
governor  is  set,  and  starting  or  speeding  up  the  pump  as  the  vacuum  drops 
below  this  point. 

The  pump,  where  of  the  reciprocating  type,  is  lubricated  by  the  admission 
of  cylinder  oil  into  the  steam  supply  line  through  a  sight -feed  lubricator, 
or  if  preferred,  through  a  mechanical  force-feed  oiler,  the  latter  being  attached 

170 


to  the  pump  preferably  before  shipment  and  actuated  by  the  operation 
of  the  pump  itself. 

The  suction  valves  of  the  pump  are  protected  from  dirt  and  foreign 
material  by  a  Webster  Suction  Strainer. 

The  products  of  condensation  will  be  conveyed  by  gravity  through  the 
system  of  return  risers  and  main  vacuum-return  line  to  a  point  either  above 
or  below  the  suction  inlet  of  the  pump,  depending  upon  building  conditions. 

If  this  point  is  below,  the  vacuum  pump  will  raise  the  condensation 
with  its  entrained  air.  The  arrangement  of  "lifts"  depends  upon  the  ver- 
tical distance  and  degree  of  vacuum  created  and  maintained  by  the  pump. 

Webster  Lift  Fittings  used  in  pairs  will  materially  assist  the 
vacuum  pump  where  lifts  are  necessary. 

Various  methods  of  applying  vacuum-governors,  lubricators,  suction 
strainers  and  lift  fittings  in  connection  with  vacuum  pumps  are  shown  in 
the  Webster  Service  Details  in  Chapter  13  in  which  the  practical  problems 
of  installation  are  worked  out. 

Final  Disposal  of  the  Condensation:  The  vacuum  pump  discharges 
the  products  of  condensation  to  a  point  of  disposal,  where  the  entrained 
air  is  liberated  and  the  condensation  returned  to  the  boiler  as  feedwater. 

In  Figure  15-2  the  pump  discharges  into  a  Webster  Receiving  Tank 
which  is  vented  to  the  atmosphere.  The  condensation  flows  by  gravity 
from  the  tank  to  the  Webster  Feed-water  Heater  against  the  working 
pressure  carried. 

In  the  typical  case,  the  receiving  and  air-separating  tank  is  of  the 
water-control  type,  and  the  Webster  Feed-water  Heater  also  has  an  auto- 
matically controlled  valve  in  its  water-supply  line. 

As  the  water  level  in  the  Feed-water  Heater  lowers,  the  automatic 
valve  opens,  and  the  condensation  flows  from  the  tank  to  the  heater  through 
the  sealed  connection.  This  arrangement  of  tank  and  heater  may  be  used 
only  where  the  tank  can  be  located  at  sufficient  height  above  the  heater 
so  that  the  static  head  will  overcome  the  working  pressure  within  the  heater. 

Additional  fresh  water  required  to  make  up  any  losses  that  occur  is 
admitted  automatically  into  the  tank  by  the  lowering  of  the  water  level, 
which  in  turn  actuates  the  automatic  water-regulating  valve. 

Surplus  condensation  overflows  from  the  tank  to  the  sewer  or  drain. 
The  waste  of  condensation  at  higher  temperature  from  the  overflow  of  the 
feed-water  heater  is  thus  eliminated. 

An  alternate  arrangement  which  is  often  desirable  is  the  use  of  a 
\Vebster  Receiving  Tank  of  the  plain  type  with  a  Webster  Feed-water 
Heater  of  the  Steam-control  Type,  as  is  shown  in  Fig.  27-7,  Page  304. 

In  this  case  the  condensation  flows  continuously  from  the  tank  to  the 
heater.  As  the  water  level  in  the  heater  rises,  the  automatic  valve,  placed 
in  the  steam  line  to  the  boiler-feed  pump  and  actuated  by  the  water  level  in 
the  heater,  causes  the  pump  to  withdraw  the  water  from  the  heater. 

Another  arrangement  is  the  use  of  a  Webster  Tank  of  the  plain  type  dis- 
charging into  a  special  return  inlet  on  the  heater,  fresh  water  as  needed 
being  automatically  admitted  into  the  heater.  (See  Fig.  27-6,  Page  303.) 

Still  another  arrangement  which  is  necessary  where  the  tank  cannot  be 

171 


located  at  sufficient  height  above  the  heater  to  overcome  the  pressure  therein, 
is  the  use  of  a  Webster  Hydro-pneumatic  Tank,  described  in  Chapter  13. 

Where  an  open  feed-water  heater  is  not  used,  the  tank  discharges  to  the 
boiler-feed  pump,  either  the  water-control  or  steam-control  type  of  pump 
being  used,  according  to  conditions. 

The  specific  functions  of  each  of  these  types .  of  Webster  Receiving 
Tanks  are  more  particularly  described  in  Chapter  24. 

Ventilation  Problems:  In  Figure  15-2  a  typical  installation  of  a  motor- 
driven  ventilating  fan,  with  its  re-heater  and  tempering  coils,  is  also  shown. 

The  fan  heater  supply  line  is  dripped  through  a  Webster  Return  Trap 
and  Dirt  Strainer,  and  the  individual  heater  sections  through  Webster 
Return  Traps. 

The  method  of  dripping  fan  heater  sections  will  vary  with  the  size, 
arrangement  and  number  of  sections.  Special  study  should  be  made  of  the 
various  Webster  Service  Details  shown  in  Chapter  22. 

It  is  exceedingly  important  not  only  to  choose  the  right  type  of  trap 
for  use  with  indirect  radiators  but  also  to  have  the  pipe  connections  properly 
made.  The  trap  must  be  of  the  highest  efficiency,  with  sufficient  capacity 
to  pass  rapidly  the  maximum  quantities  of  water  and  air  which  are  present 
when  first  warming  up,  and  afterwards  open  for  the  condensate  and  entrained 
air  but  absolutely  prevent  the  escape  of  steam.  This  must  be  done  even 
where  core  sand  and  greases  are  present  and  settle  in  the  valve  bodies.  WThere 
groups  of  radiators  are  made  up  of  large  numbers  of  sections  nippled  to- 
gether, there  is  a  likelihood  of  air-binding  sometimes  extending  over  con- 
siderable areas.  This  trouble  can  be  avoided  if  the  traps  and  piping 
are  right.  Webster  Return  Traps  and  Webster  Heavy-duty  Traps  meet 
every  condition  if  installed  in  accordance  with  proper  Service  Details. 

Further  reference  should  also  be  made  to  other  chapters  for  description 
and  method  of  application  of  various  types  of  Webster  Feed-water  Heaters 
where  power  boilers  are  used  for  generating  steam  for  prime  movers ;  Webster 
Steam  Separators  placed  in  the  high-pressure  steam  lines  to  provide  dry 
steam  for  engines;  and  Webster  Expansion  Joints,  of  both  the  single  and 
double-slip  pattern,  for  low  and  high-pressure  steam  lines,  to  take  care  of 
the  expansion  and  contraction  which  occur  in  such  lines. 

2.  WEBSTER  VACUUM  SYSTEM  WITH  MEDIUM-PRESSURE  BOILERS, 
15  TO  50-LB.:  The  foregoing  description  will  serve  as  a  general  description 
of  this  type  of  vacuum  system,  except  that  the  feed-water  heater  will  not 
be  used,  the  exhaust  steam  will  be  limited  to  that  from  pumps  and  auxiliaries, 
if  steam-driven,  and  the  vacuum  pump  will  be  either  of  the  low-pressure 
steam-driven  type  or  electrically  driven. 

Under  some  conditions,  particularly  for  pressures  up  to  20-lb., 
electrically  driven  pumps  may  be  more  suitable,  and  in  these  cases  the 
lubricator  and  vacuum-pump  governor  will  not  be  used. 

For  boiler  pressures  up  to  15-lb.,  either  electrically  operated  re- 
ciprocating vacuum  pumps  or  steam-driven  pumps  can  often  be  used  in 
conjunction  with  Webster  Hydro-pneumatic  Tanks  to  return  the  water  to 
the  boiler  without  the  use  of  a  separate  boiler-feed  pump.  Webster  Service 
Details  in  Chapter  13  show  the  proper  arrangement  for  such  cases. 

172 


3.  WEBSTER  VACUUM  SYSTEM  WITH  LOW-PRESSURE  BOILERS,  UP  TO 
15-LB. :    The  description  of  this  type  of  vacuum  system  is  the  same  as  that 
immediately  preceding,  except  that  the  rotary  type  of  electrically  driven 
vacuum  pump,  handling  air  and  water  separately,  is  particularly  suitable. 
These  pumps  also  act  as  boiler-feed  pumps  if  the  conditions  of  the  plant 
are  within  the  range  of  the  discharge  head  or  pressure  at  which  the  manu- 
facturers guarantee  these  pumps  to  operate. 

4.  WEBSTER    VACUUM    SYSTEM.    STEAM    FURNISHED    FROM    STREET 
SYSTEM:     As  steam  at  a  pressure  suitable  for  operating  a  steam-driven 
vacuum  pump  is  usually  not  available,  this  type  of  vacuum  system  will 
require  either  rotary  or  reciprocating  electrically  driven  vacuum  pump. 

The  condensation  in  such  cases  is  discharged  to  the  sewer  or  point 
of  disposal  through  a  condensation  meter  of  a  type  for  vacuum  service. 

WEBSTER  VACUUM  SYSTEMS,  SPECIAL  MODIFICATIONS:  There  are 
two  special  types  of  modifications  of  Webster  Vacuum  Systems  which  will 
require  special  description:  The  Webster  Conserving  System  and  the 
Webster  Hylo  Vacuum  System. 

WEBSTER  CONSERVING  SYSTEM:  This  is  a  special  modification  of  the 
Webster  Vacuum  System  which  meets  two  general  conditions: 

1.  Where  necessary  to  operate  steam-driven  pumps  from  low-pressure 
boilers  at  very  low  pressure — from  5  to  20-lb. 

2.  Where  necessary  to  provide  steam  for  some  special  service  con- 
tinuously at  a  pressure  higher  than  that  needed  for  heating. 

Referring  to  Figure  15-3,  this  system  is  in  general  respects  similar  to 


Globe  Valve 
WEBSTER 
DAMPER 
rsREGULATOR 


^•-"T-r 

WEBSTER 

CONSERVING  VALVE 


This  Connection  to  be  made  1 5'-  0" 

from  Pressure  Reducing  Valve 
WEBSTER 
WATER  ACCUMULATOR 


Gauge 


Pressure  Reducing  Valve 


Provide  Pel  Cock  for 
venting  Diaphragm 


WEBSTER  HORIZONTAL 
OIL  SEPARATOR 


WEBSTER  SINGLJE 
CONTROL  HY- 

DROPNEUMATIC 
TANK 

Discharge  from 
Tank  to  Boiler 


WEBSTER 

VACUUM  PUMP 

GOVERNOR 


This  Valve  to  be  open  when 
Pump  Is  started  and  closed 
when  Pump  Is  in  operation 


Globe  Valve 
Check  Valve 


Bypass  to  Sewer'          I    'WEBSTER  SUCTION  SIRAINER 
WEBSTER  LIFT  FITTINGS 

Fig.  15-3.    Typical  layout  of  a  Webster  Conserving  System 
173 


^WEBSTER  GREASE 
AND  OIL  TRAP 


the  vacuum  system  described  for  working  pressures  from  15  to  50-lb.  pressure. 

A  low-pressure  steam-driven  vacuum  pump  is  used,  discharging  to  a 
Webster  Hydro-pneumatic  Tank,  and  thence  to  the  boiler  against  pressure. 

The  distinguishing  feature  of  this  special  system  is  the  Webster  Con- 


Fig.  15-4.     Typical  installation  and  close-up  of  the  Webster  Conserving  Valve 

174 


serving  Valve,  which  is  placed  in  the  supply  main  near  the  boiler,  and 
conserves  or  retains  the  steam  on  the  inlet  side  of  the  valve  until  sufficient 
pressure  has  been  built  up  to  (1)  operate  the  pump,  or  (2)  meet  the  pressure 
requirements  of  the  special  service. 

Connections  to  the  vacuum  pump  or  for  the  special  service  are  taken 
from  the  high-pressure  side  of  the  conserving  valve.  When  the  predeter- 
mined pressure  has  been  built  up,  the  excess  pressure  is  released  into  the 
heating  main  by  means  of  the  conserving  valve. 

In  consequence,  the  vacuum  pump  begins  to  function  before  the  steam 
enters  the  heating  main  and  continues  to  operate  even  when  the  pressure 
drops  on  the  high-pressure  side  to  such  point  that  the  conserving  valve  closes 
against  further  admission  of  steam  into  the  heating  main.  The  heating 
system  is  therefore  kept  continuously  drained  of  water  at  all  times,  insuring 
return  of  condensation  to  the  boiler  and  preventing  accidents  or  damage 
which  would  occur  from  lowering  the  boiler  water  level  to  a  dangerous  point. 

One  other  special  feature  of  this  system  is  the  use  of  a  Webster  Damper 
Regulator  to  control  the  boiler  pressure,  operating  from  the  low-pressure 
side  of  the  conserving  valve.  The  damper  regulator  must  be  connected 
in  the  special  manner  recommended. 

In  a  similar  manner  to  the  above,  any  special  apparatus  like  kitchen 
equipment  requiring  steam  continuously  at  higher  pressure  is  always 
assured  of  constant  supply  regardless  of  operation  of  the  heating  system. 

Another  adaptation  of  the  Webster  Conserving  System  is  in  large 
plants  in  which  the  engines  are  run  condensing. 

A  study  of  steam  engine  performance,  where  the  engine  exhausts  into 
the  atmosphere  or  into  the  heating  system  aga  nst  a  back  pressure  slightly 
above  that  of  the  atmosphere,  shows  that  engines  working  under  such 
conditions  actually  convert  only  5  to  10  per  cent  of  the  heat  supplied  to 
them  into  mechanical  energy.  The  remaining  90  per  cent  of  the  heat  origi- 
nally supplied  to  the  steam  entering  the  engine  is  retained  in  the  exhaust. 

In  some  plants,  power  and  heating  loads  are  nicely  ba  anced  so  that  all 
the  exhaust  steam  available  from  power  units  can  be  utilized  for  process  work 
or  heating  purposes,  in  which  event  the  90  per  cent  of  heat  energy  remaining 
in  the  exhaust  steam  is  put  to  useful  work.  In  such  cases  the  engine  may  be 
considered  as  a  pressure-reducing  valve  wrhich  reduces  the  pressure  from 
that  carried  on  the  boilers  to  that  required  for  heating  and  process  purposes. 

There  are  numerous  industrial  plants  where  the  power  load  is  greatly 
in  excess  of  the  heating  load,  so  that  the  quantity  of  exhaust  steam  available 
is  greatly  in  excess  of  that  actually  required.  The  surplus  exhaust  steam 
with  its  heat  units  must  then  be  wasted. 

Where  these  conditions  exist,  the  engines  are  often  operated  condensing 
instead  of  non-condensing,  so  that  exhaust  steam  from  the  auxiliary  ma- 
chinery only  is  available.  In  most  instances  the  quantity  is  not  sufficient 
to  supply  the  heating  load,  and  the  deficiency  is  made  up  by  live  steam 
supplied  from  the  boiler  through  a  pressure-reducing  valve. 

The  work  done  by  the  pressure-reducing  valve  in  reducing  the  steam 
from  boiler  pressure  to  that  required  in  the  heating  system  is  converted 
into  superheat  on  the  low-pressure  side  of  the  valve.  This  work  represents 

175 


about  10  per  cent  of  the  total  heat  energy  supplied  to  the  steam.  If  this  10 
per  cent  of  heat  energy  can  be  utilized  by  conversion  into  mechanical  energy, 
nearly  ideal  conditions  will  be  approached. 

Various  attempts  have  been  made  in  the  past  to  improve  the  economy 
of  power  and  heating  plants  by  endeavoring  to  utilize  the  exhaust  steam 
from  the  receivers  of  compound  engines.  This  exhaust  is  bled  into  the  heat- 
ing system  and  the  deficiency  made  up  by  admitting  live  steam  into  the 
receiver  through  a  pressure-reducing  valve.  In  determining  the  advisability 
of  this  form  of  application,  the  effect  of  the  relations  between  heating  and 
power  load  and  the  relative  proportion  of  the  cylinders  so  vitally  affects 
the  economy  that  in  each  instance  special  consideration  has  to  be  given  to 
all  elements  entering. 

The  Webster  Conserving  System  can  be  applied  to  this  problem.  In 
the  same  manner  that  the  conserving  valve  is  applied  to  conserve  the 
pressure  on  the  boiler  by  preventing  the  escape  of  its  steam  until  a  certain 
predetermined  pressure  is  obtained,  it  can  be  applied  to  the  receiver  of  a 
compound  engine,  opening  and  admitting  steam  at  receiver  pressure  into 
the  heating  system,  when  the  pressure  on  the  receiver  exceeds  that  which 
is  necessary  for  the  proper  operation  of  the  low-pressure  cylinder,  and 
closing  when  the  receiver  pressure  drops  below  the  point  for  which  the  con- 
serving valve  is  set. 

The  quantity  of  steam  taken  from  the  receiver  is  made  up  by  changing 
the  cut-off  on  the  high-pressure  cylinder  so  that  the  high-pressure  side 
acts  as  a  pressure-reducing  valve  for  the  steam  required  for  heating  purposes. 
In  expanding  from  boiler  pressure  to  the  receiver  pressure,  the  heat  energy 
given  up  in  the  expansion  is  converted  into  useful  mechanical  energy. 

By  means  of  the  Webster  Conserving  System  many  existing  power  and 
heating  plants  may  be  brought  to  efficiency  where  they  are  otherwise 
wasteful  of  steam. 

WEBSTER  HYLO  VACUUM  SYSTEM:  Where  a  number  of  buildings 
must  be  heated  from  a  detached  central  plant,  or  where  a  building  covers 
considerable  ground,  the  source  of  steam  supply  and  of  vacuum  cannot 
always  be  located  to  make  a  well-balanced  system. 

The  largest  building  in  the  group  may,  for  various  reasons,  be  farthest 
from  the  source  of  supply,  and  may  also  be  the  lowest  point  in  the  system 
of  return  piping,  thus  making  it  doubly  difficult  to  secure  perfect  heating 
and  easy  return  of  condensation.  Nearby  points  may  be  favored  with 
unnecessary  pressure  difference. 

Attempts  have  been  made  to  solve  this  problem  by  running  the  supply 
and  return  mains  in  reverse  direction,  so  that  the  point  of  highest  pressure 
is  the  point  of  lowest  vacuum  and  inversely,  thus  maintaining,  in  some 
degree,  the  same  differential  between  supply  and  return  pressures. 

Where  the  largest  building  is  at  a  low  point  away  from  the  source  of 
supply,  it  is  obviously  impracticable  to  solve  the  problem  in  this  way. 
Furthermore,  such  a  plan  does  not  allow  for  extensions  to  or  expansion  of 
the  plant,  unless  the  new  buildings  can  be  located  to  suit  the  piping 
scheme,  irrespective  of  the  manufacturing  need. 

This  problem  has  been  solved  with  unqualified  success  by  Webster 

176 


Gauge  Cock 
Bushing 


Overhead  Return 

from  Heating 

System 


Gauge  Cock        %! 

•»  Bushing  oJ 


urn-J 

P 


Gate  Valve 


Floor  Line- 


Fig.  15-5.  Connections  around 
Webster  Hylo  System  equip- 
ment where  the  low-vacuum 
return  main  drops  from  over- 
head and  discharges  through 
a  Webster  Hylo  Trap  to  the 
high-vacuum  return  main 


Fig.  15-6.  Typical  installation 
of  Webster  Hylo  Trap,  Con- 
troller and  Gauges  where  high 
and  low-vacuum  returns  are 
on  the  same  level 


Gauge  Cock 


WEBSTER 
HYLO  COMBINATION  GAUGES 


\WEBSTER 
HYLO  VACUUM  CONTROLLER 


Gate  Valve 


Floor  Line  -• 


WEBSTER 
HYLO  VACUUM  CONTROLLER  Union 


Fig.  15-7.  Arrangement 
of  the  Webster  Hylo 
Controller,  Trap  and 
Gauges  where  the  low- 
vacuum  return  is  lifted 
to  the  high-vacuum 
return 


177 


Hylo  Vacuum  Controlling  Sets,  which  are  installed  at  certain  points  in  the 
return  line  to  restrict  the  vacuum  to  just  the  amount  necessary  for  proper 
circulation  and  drainage  at  nearby  points  where  high  vacuum  is  not  needed. 
The  high  vacuum  is  carried  to  extreme  or  low  points  where  high  vacuum 
is  required.  The  result  is  a  well-balanced  system  with  perfect  circulation 
in  all  parts. 

The  operation  of  the  vacuum  pump  is  also  improved  to  a  marked  extent 
as  the  degree  of  initial  vacuum  is  reduced,  making  it  unnecessary  to  use  or 
waste  cold  water  to  condense  the  vapors  arising  from  the  hot  water  returned 
under  high  vacuum.  Sometimes  smaller  pumps  may  be  used,  or  the  pumps 
may  be  operated  at  slower  speed  with  less  wear  and  tear. 

The  Webster  Hylo  Sets  consist  of  a  Webster  Hylo  Trap,  a  Webster 
Hylo  Vacuum  Controller,  Webster  Hylo  Vacuum  Gauges,  and  when  needed, 
Webster  Lift  Fittings. 

Figures  15-5, 15-6  and  15-7  show  various  methods  of  connecting  Webster 
Hylo  Sets  to  meet  different  building  conditions. 


178 


CHAPTER  XVI 

Application  of  the  Webster  System  to  Lumber  and 
Other  Kiln  Drying  Problems 

PROPER  seasoning  and  drying  of  raw  lumber  is  a  first  essential  to  well- 
finished  products  in  any  wood-working  industry. 
This  basic  condition  makes  the  dry  kiln  or  room  a  most  important 
feature,  for  as  proved  by  experience  in  many  instances,  lumber  that  was  found 
defective  when  worked  would  have  been  satisfactory  if  proper  methods  had 
been  applied  for  drying.     Very  careful  attention  should  therefore  be  given 
to  the  design  of  the  drying  room,  the  character  of  apparatus  used  and  the 
heating  medium  employed. 

The  method  to  be  employed  in  drying  will  depend  entirely  upon  the 
condition  of  the  product  when  put  in  the  kiln.  Green  lumber,  or  lumber 
having  a  high  percentage  of  moisture,  will  require  a  different  method  of 
procedure,  and  a  longer  time  to  dry  than  lumber  which  has  been  air  dried. 
Hard  woods  such  as  oak  or  hard  maple  usually  require  a  longer  time  than 
soft  woods. 

Saw  mills  should  determine  the  percentage  of  free  moisture  by  test  and 
so  mark  each  pile  of  lumber  when  first  piled  in  the  yard.  Later,  when  it  is 
sold,  the  lumber  should  be  tested  again  and  the  two  records  given  to  the 
factory  or  other  purchaser. 

Factories  should  test  and  mark  the  lumber  when  first  received,  and  if 
it  is  piled  in  the  yard  to  be  kiln  dried  later,  it  should  be  tested  before  going 
to  the  kiln  and  again  before  removal,  these  records  being  placed  on  file. 

The  process  required  for  the  drying  of  lumber  in  kilns  is  properly 
divided  into  four  parts,  as  follows: 

First :  The  primary  treatment,  during  which  all  dampers  are  closed, 
100  per  cent  humidity  is  maintained  and  the  stock  is  warmed  through 
without  drying. 

Second :  The  initial  drying  period,  during  which  the  conditions  of  tem- 
perature and  humidity  within  the  kiln  are  advanced  sufficiently  to  reduce 
the  moisture  content  to  25  per  cent. 

Third:  The  intermediate  drying  period,  during  which  drying  condi- 
tions are  still  more  advanced  to  reduce  the  moisture  content  to  10  per  cent. 

Fourth :  A  final  drying  period,  during  which  extreme  conditions  are 
used  to  further  reduce  the  moisture  content  to  the  percentage  desired. 

Improper  drying  methods  will  usually  result  in  one  or  more  of  the  fol- 
lowing conditions: 

(1)  Percentage  of  moisture  not  correct  for  working,  (2)  case  hardening, 
(3)  hollow-horning  or  honey-combing,  (4)  molding. 

The  operator  should  make  careful  test  readings  to  determine  the  mois- 
ture content  both  before  and  during  the  drying  of  the  lumber. 

Records  from  such  tests  will  give  data  on  which  to  base  his  treatment 
of  the  stock.  Tests  should  be  made  at  stated  intervals  of  48  to  72  hours 


179 


during  the  drying  period.  For  this  purpose  test  boards  from  which  samples 
may  be  taken  should  be  inserted  in  the  kiln.  A  good  solid  heavy  piece  as  a 
sample,  or  better  still,  two  or  more  sections  out  of  as  many  different  boards 
taken  out  of  the  pile  one-third  the  distance  from  the  bottom,  will  yield  an 
average  or  representative  test  for  moisture  content.  With  two  or  more 
tests  for  moisture  showing  varying  results,  it  is  safer  to  use  readings  showing 
the  highest  moisture  content  rather  than  the  average  of  the  pieces. 

At  the  same  time,  tests  should  be  made  for  case  hardening.  If  the 
lumber  becomes  case  hardened,  it  practically  stops  the  drying  process,  or 
at  least  slows  it  to  a  great  extent.  Frequently  this  results  in  hollow-horning, 
cupping,  internal  strains  and  many  other  evils  which  affect  the  stock  through- 
out the  manufacturing  process. 

Almost  all  "working"  which  occurs  in  furniture,  or  other  wood  articles, 
is  due  to  stresses  which  developed  in  the  wood  during  the  seasoning  period. 
These  stresses  may  be  determined  by  two  simple  tests  and  eliminated  before 
the  stock  leaves  the  kiln. 

The  manufacturers  of  the  different  makes  of  dry  kilns  furnish  detailed 
instructions  for  the  various  tests  on  which  the  successful  operation  of  their 
kilns  depend. 

The  final  condition  of  the  lumber  required  in  different  factories  varies 
with  the  purpose  for  which  the  lumber  is  used.  For  instance,  in  wagon 
work,  many  manufacturers  do  not  use  lumber  containing  less  than  10  to 
12  per  cent  of  moisture;  in  auto  body  work,  for  open  bodies,  6  to  8  per  cent 
is  considered  proper;  for  closed  bodies,  5  to  6  per  cent.  Furniture  manufac- 
turers generally  dry  down  to  4  to  6  per  cent,  while  wheel  manufacturers 
dry  the  spokes  as  nearly  bone  dry  as  possible,  but  do  not  dry  the  felloes 
below  8  per  cent,  the  theory  being  that  when  the  wheel  is  made  the  spokes 
may  absorb  moisture  and  make  a  snug  fit. 

A  modern  kiln  is  usually  constructed  with  brick  side  walls  and  a  roof 
of  tile  or  cement  covered  with  roofing  felt,  tar  and  gravel.  The  doors  are 
of  special  design  to  allow  for  easy  loading  and  unloading,  and  to  prevent,  as 
much  as  possible,  air  leakage  and  loss  of  heat.  Ventilating  flues  are  provided 
in  the  side  walls  for  supplying  air  and  removing  same  as  desired. 

The  heating  medium  usually  employed  is  steam  at  varying  pressures, 
depending  upon  the  kiln  temperature  desired.  The  temperature  within 
the  kiln  is  controlled  by  means  of  a  thermostat  operating  a  valve  in  the  pipe 
supplying  steam  to  the  coils. 

A  system  of  steam  spray  pipes  is  provided  under  the  material  to  be  dried 
for  increasing  the  humidity  as  desired  and  to  assist  in  warming  the  stock. 
The  percentage  of  humidity  in  the  kiln  may  be  automatically  controlled  by 
means  of  a  humidistat  operating  a  valve  controlling  the  supply  of  steam  to 
the  spray  pipes. 

Where  steam,  whether  exhaust  from  engines  and  auxiliaries,  or  taken 
direct  from  the  boilers,  is  used  as  a  heating  medium,  the  success  of  the 
drying  equipment  depends  upon  the  manner  of  carrying  this  steam  to  the 
heating  units,  the  proper  drainage  of  the  supply  mains,  the  circulation  of 
the  steam  through  the  heating  units  and  the  removal  of  air  and  water  of 
condensation. 


180 


All  manufacturers  of  drying  equipment  utilizing  steam  as  a  heating 
medium  recognize  the  importance  of  these  features.  One  of  the  largest 
manufacturers  of  drying  equipment  in  the  United  States  says  in  its  book  of 
instructions : 

"Where  troubles  have  been  experienced,  investigations  have  shown  that 
they  are  generally  due  to  one  or  more  of  the  following  conditions: 

'  Poor  steam  service. 

'  Pressure  not  constant. 

'Wet  steam  due  to  improper  condensation  drainage. 

'  Insufficient  steam  pressure. 

'  Poor  drainage  from  traps. 

'  Improper  design  of  supply  and  drainage  piping. 

'Traps  allowing  steam  to  blow  through  into  the  main  drainage  line, 
holding  back  kiln  drainage. 

'Traps  on  heating  units  not  functioning  properly. 

'Traps  stopped  with  scale  or  dirt. 

'Trouble  is  often  caused  by  faulty  design  in  making  steam  connections 
to  kilns. 

"  All  steam  lines  must  pitch  in  the  direction  of  steam  flow.  Automatic 
drain  traps  must  be  provided  at  all  low  points  on  these  lines  in  order  that 
there  may  be  absolutely  no  condensation  lying  in  the  lines  at  these  places, 
and  that  steam  may  enter  the  kiln  dry  and  at  a  high  temperature.  Failure 
to  provide  proper  methods  of  drainage  will  result  in  reduced  volume  and 
temperature  of  steam  and  correspondingly  low  temperatures  and  poor  serv- 
ice in  dry  kilns." 

The  important  features  in  connection  with  the  steam  supply  and  drain- 
age system  can  be  enumerated  as  follows. 

(1)  Adequate  and  continuous  supply  of  steam.     Pressure  of  steam  con- 
stant and  sufficient  to  produce  the  required  temperature  within  the  kilns. 

(2)  Manner  of  conveying  steam  to  coils. 

(3)  Method  of  draining  main  steam  supply. 

(4)  Character  of  design  of  heating  units. 

(5)  Method  of  complete  and  rapid  air  removal  from  heating  units  and 
from  entire  return  system. 

(6)  Method  of  removal  of  condensation  from  heating  units. 

(7)  System  of  drainage  piping. 

(8)  Ultimate  disposal  of  water  of  condensation  and  of  air. 

(9)  Adequate  and  continuous  pitch  of  pipes  throughout  the  entire 
length  of  the  coil. 

Items  one,  seven  and  eight  will  be  governed  materially  by  the  condi- 
tions existing  at  the  plant  where  kilns  are  to  be  used,  and  as  these  conditions 
vary  with  the  character  of  the  plant,  this  discussion  will  be  limited  to  the 
requirements  of  the  kiln  only. 

The  pressure  of  steam  supply,  so  far  as  the  operation  of  the  kiln  is  con- 
cerned, will  depend  upon  the  temperature  required  within  the  kiln.  If  a 
maximum  kiln  temperature  of  not  more  than  150  deg.  fahr.  is  required,  satis- 
factory results  can  be  obtained  by  the  use  of  exhaust  steam  from  engines 
and  auxiliaries  at  a  pressure  not  to  exceed  lJ/2-lb.  gauge.  The  same  results 

181 


C__] 


Vacuum  Return 


A  Typical  Elevation 


A  Typical  Plan 

Fig.  16-1.     Sections  through  a  typical  dry  kiln  with  coils  of  the  continuous-header  type  using  Webster 
Heavy-duty  Traps  for  drainage  and  Webster  Return  Traps  for  removal  of  air  from  return  headers 

182 


will  be  obtained,  of  course,  by  using  steam  direct  from  the  boiler,  reduced 
to  a  corresponding  pressure  by  means  of  reducing  valves.  It  is  very  impor- 
tant to  place  a  relief  valve  on  the  low  pressure  side  of  the  reducing  valve  to 
prevent  rise  of  steam  pressure  to  a  point  where  there  is  a  liability  of  injur- 
ing the  thermostatic  return  traps.  The  details  are  shown  in  Fig.  22-3, 
Page  216. 

Where  temperatures  greater  than  160  deg.  fahr.  are  required  it  will  be 
necessary  to  increase  the  pressure  of  the  steam  accordingly.  In  good 
practice  the  temperature  of  the  steam  must  not  be  less  than  60  degrees 
higher  than  the  temperature  desired  in  the  kiln. 

The  size  of  the  steam  supply  mains  will  depend  upon  the  volume  of 
steam  to  be  delivered,  and  the  drop  in  pressure  allowable.  This  may  be 
determined  with  the  help  of  the  tables  in  Chapter  11  in  this  book  after  a 
decision  has  been  reached  as  to  the  total  heat  requirements  of  the  kiln  and 
the  distance  of  the  kiln  from  the  source  of  steam  supply.  The  same  prin- 
ciples apply  for  the  installation  of  steam  mains  to  the  kilns  as  would  apply 
for  the  installation  of  steam  mains  for  any  other  purpose. 

Extreme  care  should  be  given  to  the  drainage  of  the  steam  main  at  the 
point  of  entrance  to  the  kiln.  It  is  advisable  that  water  of  condensation 
from  the  main  shall  be  relieved  from  the  bottom  into  the  return  and  that 
steam  for  kilns  shall  be  taken  from  the  top  of  the  main  rather  than  to  allow 
the  condensation  to  drain  through  the  coils.  The  supply  main  may  enter 
the  kiln  from  a  point  above  the  coils  used  for  heating,  or  from  below  them. 

Manufacturers  of  drying  equipment  have  devised  numerous  types  of 
heating  units  but  practically  all  have  standardized  on  those  constructed  of 
pipe.  The  coils  are  placed  either  vertically  along  the  side  walls  of  kiln,  or 
horizontally  in  a  space  provided  underneath  the  material  to  be  dried.  In 
the  latter  instance  they  are  usually  installed  in  a  horizontal  position,  although 
some  manufacturers  prefer  coils  placed  vertically.  The  advantage  of  more 
equal  heat  distribution  is  claimed  for  the  large  unit  laid  horizontally,  but  this 
is  not  fully  realized  unless  the  removal  of  air  and  condensation  is  complete. 

With  coils  having  short  vertical  headers,  say  10  pipes  high,  it  is  very 
important  to  secure  an  equal  distribution  of  steam  to  all  of  the  pipes.  The 
internal  diameter  of  the  supply  header  should  be  ample;  2*/£-in.  is  none 
too  great.  It  is  very  important  not  to  locate  the  inlet  in  such  a  position 
that  steam  will  enter  those  pipes  directly  in  front  of  it  and  passing  through 
to  the  return  header,  tend  to  pocket  the  air  in  the  other  pipes.  The  re- 
moval of  air  will  be  very  sluggish  and  meanwhile  the  efficiency  of  the  whole 
coil  will  be  low.  A  deflector  placed  within  the  header  in  front  of  the  inlet 
will  improve  the  steam  distribution.  A  much  better  method  is  to  have 
more  than  one  inlet.  These  additional  supply  connections  will  also  reduce 
materially  the  velocity  of  the  entering  steam. 

Figs.  22-21  and  22-22,  on  Page  220,  show  methods  of  splitting  up  the 
return  header  into  two  parts,  for  coils  of  more  than  10  pipes,  when  there  is 
a  liability  of  air  binding. 

With  horizontal  headers,  particularly  where  of  some  length,  the  in- 
ternal diameter  should  be  large  and  the  number  and  location  not  only  of 
supply  openings  but  also  of  return  and  air  vent  outlets  should  be  selected 

183 


with  great  care,  so  as  to  ensure  uniform  distribution  of  steam  and  complete 
removal  of  air  and  water. 

Practical  experience  has  demonstrated  that  incomplete  removal  of  air 
and  condensation  has  caused  unequal  heat  distribution  throughout  the 
kiln  as  well  as  a  drop  in  temperature  of  from  20  to  50  per  cent.  The  air 
must  not  only  be  removed  from  the  coils  but  also  must  be  rapidly  and 
completely  eliminated  from  the  return  system  and  discharged  outboard. 

The  selection  of  the  proper  type  of  trap  to  be  used  in  any  given  case 
depends  upon  the  steam  pressure  which  it  is  necessary  to  carry  on  the  coils 
to  secure  the  requisite  heating  effect,  the  quantity  of  water  which  the  trap 
must  handle,  the  temperature  of  the  room  in  which  the  trap  is  installed, 
the  pressure  in  the  discharge  line  and  the  disposition  to  be  -made  of  the 
products  of  condensation. 

A  continuous  and  uniform  steam  pressure  of  not  over  3  to  5  lb.,  a 
moderate  and  uniform  quantity  of  condensation  to  be  handled,  and  a  tem- 
perature of  not  over  80  deg.  in  the  space  where  the  traps  are  located,  are 
the  most  favorable  conditions  for  the  successful  operation  of  low  pressure 
thermostatic  traps.  They  should  not  be  employed  where  the  temperature 
requirements  of  the  kiln  necessitate  carrying  a  continuous  steam  pressure  which 
approaches  closely  the  allowable  maximum  pressure  of  the  trap.  Traps  on  high 


Plan 

Fig.  16-2.     Typical  section  through  a  dry  kiln  using  coils  of  the  sectional-header  type 

184 


Pipe  Supply 
\  Supply  lo 
.  \Sorav  Pice 


Elevation 


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Fig.  16-3.     Sectional  drawings  of  a  typical  small  dry  kiln  using  individual  return  traps  for  drainage  of  coils 


185 


pressure  steam  drips  must  never  be  permitted  to  discharge  directly  into  the 
return  pipe  near  the  thermostalic  traps  on  account  of  the  liability  of  back 
pressure  or  water  hammer.  The  connection  should  be  made  at  a  point  be- 
yond the  traps,  placing  a  check  valve  in  the  thermostatic  trap  return  to 
prevent  back  pressure  therein  and  in  addition  means  should  be  employed 
for  disposing  of  the  high  temperature  vapor  as  shown  in  Fig.  20-2,  Page  203. 

The  types  of  heating  units  which  are  universally  used  and  the  manner 
of  applying  the  Webster  specialties  for  proper  air  removal  and  drainage  of 
condensation  are  shown  in  Figs.  16-1  to  16-4  inclusive.  Attention  is  called 
to  the  importance  of  providing  a  dirt  strainer  for  the  drain  connection  to 
each  trap.  Both  the  traps  and  strainers  should  be  readily  accessible. 
Where  thermostalic  traps  are  used  they  should  be  located  where  they  will  not 
be  affected  by  the  high  temperatures  of  the  kiln.  This  is  usually  accomplished 
by  extending  drain  connections  to  the  extreme  front  or  rear  of  the  kiln  and 
placing  the  traps  near  the  floor. 

On  small  units  as  shown  in  Figure  16-3,  where  thermostatic  traps  are 
used,  additional  provision  for  the  removal  of  air  is  unnecessary,  but  where 
a  large  volume  of  condensation  accumulates,  additional  provision  for  air 
removal  is  essential  and  heavy-duty  traps  should  be  used.  Where  the  heating 
unit  is  of  the  continuous  header  type  as  shown  in  Figure  16-1  the  air  removal 
can  be  accomplished  by  the  use  of  heavy-duty  traps  equipped  with  a  ther- 
mostatically actuated  air  bypass  within  the  trap  and  by  means  of  additional 
thermostatically  actuated  air  traps  connected  into  the  top  of  the  main 
return  header,  as  shown  in  Figures  16-1,  16-2  and  16-4.  The  number  and 
location  of  these  air  traps  is  governed  by  the  length  and  design  of  the  main 
return  header.  The  outlets  of  these  air  return  traps  should  be  connected 
into  the  main  vacuum  return  line  beyond  the  discharge  connection  of  the 
heavy-duty  trap. 

Where  heavy-duty  traps  are  used  there  should  be  a  drop  leg  of  from 
8  to  10  inches  between  the  outlet  on  the  return  header  and  the  trap  inlet. 

W7here  it  is  desired  to  drain  the  condensation  from  two  or  more  coils 
to  one  heavy-duty  trap,  or  where  the  return  header  of  the  coils  is  of  special 
construction  divided  into  two  or  more  sections  and  the  condensation  from 
all  sections  is  drained  by  one  trap,  it  is  essential  for  the  proper  removal  of  air  to 
equip  each  return  header,  or  each  section  of  the  return  header,  with  a  ther- 
mostatically actuated  return  trap.  The  outlets  of  these  traps  should  be 
connected  into  the  main  vacuum  return  line  in  the  same  manner  as  de- 
scribed above. 

Pipe  coils  and  return  pipe  connections  to  traps  must  have  a  sharp 
downward  pitch  their  entire  length  in  the  direction  of  the  flow  of  conden- 
sation. The  coil  supports  must  be  of  a  permanent  character  and  so  arranged 
that  any  subsequent  settlement  of  the  kiln  structure  will  not  affect  the 
pitch  of  the  pipes. 

The  discharge  from  all  heavy-duty  traps  and  thermostatically  actuated 
return  traps  used  in  connection  with  kilns  may  be  connected  into  a  com- 
mon return  line,  but  it  is  preferable  that  this  return  line  from  kilns  shall 
be  extended  independently  from  the  kilns  to  the  vacuum  pump,  rather  than 
to  connect  it  into  returns  from  the  heating  system  of  the  manufacturing 

186 


plant  or  other  equipment.  The  condensation  rate 
from  the  kilns  will  fluctuate,  depending  upon  the 
temperature  within  the  kiln,  the  nature  and  con- 
dition of  the  product  being  dried  and  the  outside 
temperature.  Consequently,  at  times  when  the 
air  removal  and  condensation  rate  from  the  kilns 
is  high,  trouble  may  be  experienced  with  the 
operation  of  other  equipment  if  connected  to  the 
same  return  line.  Also,  if  the  same  efficient 
equipment  is  not  used  in  connection  with  the 
heating  system  or  other  equipment,  as  is  used  in 
connection  with  the  kilns,  the  poor  operation  of 
the  heating  system  or  other  equipment  will  natur- 
ally reflect  in  unsatisfactory  operation  of  the 
kilns. 

The  amount  and  location  of  radiation  in- 
stalled within  the  kiln  will  depend  upon  the  loca- 
tion of  the  kiln,  the  temperature  desired  within 
the  kiln,  the  steam  pressure,  and  nature  of  pro- 
duct to  be  dried.  This  constitutes  a  special 
branch  of  engineering  and  engineers  thoroughly 
familiar  with  this  class  of  work  should  be  con- 
sulted. 

The  method  for  figuring  the  total  radiation 
required  by  a  given  dry  kiln  will  not  vary  from  the 
descriptions  given  in  detail  in  Chapter  5,  except 
that  during  the  warming-up  period  an  additional 
heat  factor  is  required  to  care  for  the  moisture 
content  of  the  lumber  or  other  material  being 
dried. 

Much  of  the  general  information  on  lumber  drying  was  furnished  for 
this  Chapter  by  the  National  Dry  Kiln  Co.,  of  Indianapolis,  Ind. 


1 

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WEBSTER 
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Fig.  16-1.  Showing  the  connec- 
tions where  two  or  more  coils  are 
drained  through  one  Webster 
Heavy-duty  Trap 


187 


CHAPTER  XVII 

Application  of  the  Webster  System  to  Slashers 
and  to  Cloth  and  Paper- dry  ing  Apparatus 

^ILASHERS  are  used  in  the  textile  industry  for  sizing  and  drying  warps 
i^  or  yarns  before  they  are  placed  in  looms  to  be  woven  into  cloth.  In 

these  machines,  steam  is  supplied  usually  to  two  cylinders,  of  5  and 
7  ft.  diameter,  over  which  the  yarn  passes  to  be  dried  after  sizing. 

Ordinarily  the  steam  supply  and  the  drainage  connections  are  on  op- 
posite heads  of  the  cylinders,  the  connections  passing  through  the  cored 
shafts  upon  which  the  cylinders  revolve.  Steam  is  carried  through  the 
mains  to  the  slasher  at  about  80-lb.  pressure  and  before  it  enters  the 
cylinders  is  reduced  to  between  5  and  12-lb.  per  sq.  in.  by  a  pressure-reducing 
valve.  The  steam  pressure  in  the  cylinders  of  course  always  must  be  above 
that  of  the  atmosphere  as  the  rapid  drying  of  the  materials  demands  that  the 
surface  temperature  of  the  cylinders  shall  be  above  the  atmospheric  boiling 
point. 

Owing  to  the  light  weight  of  the  metal  used  in  the  construction  of 
slashers,  vacuum  breakers,  usually  three  in  number,  are  provided  in  the 
head  of  the  discharge  side  of  each  cylinder.  These  open  when  a  partial 
vacuum  occurs  in  the  cylinder  and  prevent  collapse  of  same. 

The  condensation  is  raised  to  its  point  of  removal  from  the  slasher  by 
means  of  troughs  or  buckets,  usually  three  in  number,  attached  to  the  in- 
side cylindrical  surface.  A  pipe  attached  to  each  bucket  carries  the  conden- 
sation to  the  hollow  cylinder  shaft  and  thence  through  the  bearing  to  the 
outside.  From  there  the  condensation  goes  through  the  Webster  Traps, 
etc.,  to  the  point  of  disposal. 

The  Webster  System  for  draining  slashers  provides  the  most  efficient 
drying  effect  with  least  attention  to  the  drainage  equipment.  It  has  suc- 
ceeded in  overcoming  entirely  the  frequent  delays  and  slowing  down  of  the 
manufacturing  processes  previously  experienced  with  other  devices. 

As  will  be  seen  in  Figure  17-1,  each  cylinder  is  equipped  with  a  Webster 
Return  Trap,  a  Webster  Dirt  Strainer  and  a  bull's-eye  sight  glass. 

The  Webster  Return  Trap  permits  the  free  passage  of  air  and  water 
and  closes  against  the  discharge  of  steam.  The  Webster  Dirt  Strainer 
protects  the  trap  from  dirt  and  the  sight  glass  enables  the  operator  to  see 
whether  or  not  the  drainage  system  is  functioning. 

A  bypass  is  provided  around  the  drainage  apparatus.  When  starting 
up,  the  bypass  may  be  opened  for  a  few  minutes  to  permit  the  quick  dis- 
charge of  air.  After  starting,  the  slasher  is  drained  automatically  through 
the  Webster  equipment. 

A  pressure  sufficiently  above  that  of  the  atmosphere  must  be  carried 
in  the  cylinder  to  dry  the  goods  and  this  is  sufficient  to  discharge  the  con- 
densation and  air  through  the  Webster  Trap,  if  free  vent  to  atmosphere  is 
maintained.  There  is  no  advantage  in  connecting  the  discharge  of  the  traps 

188 


to  a  vacuum  pump  if  sufficient  vertical  distance  is  available  to  allow  a  proper 
fall  for  the  condensate  to  flow  by  gravity  to  an  open  receptacle. 

The  condensation  rate  with  this  type  of  slasher  will  vary  from  400  to 
600  Ib.  per  hr. 

One  of  the  best-known  American  manufacturers  of  slashers  states  in 
his  catalog: 

"We  strongly  recommend  the  use  of  Warren  Webster  &  Co.'s  appara- 
tus for  slasher  drainage. 

"Steam  traps  can  be  furnished  if  desired  but  we  recommend  the  use  of 
the  Webster  System  in  preference,  as  higher  economy  will  certainly  maintain 


Gate  Valve 
To  Drain'  '  WEBSTER  SIGHT  GUSS 

Fig.  17-1.     Typical  application  of  Webster  Apparatus  to  a  slasher 

189 


a  higher  rate  of  production  and  its  simplicity  lessens  the  liability  of  stoppage 
to  which  a  system  of  steam  traps  is  apt  to  be  subject  after  a  few  years  of  use. 
'  The  Webster  System  as  compared  with  a  steam-trap  system  insures 
steady,  instead  of  intermittent,  drainage  and  practically  an  entire  absence 
of  condensation  in  the  cylinder  with  all  consequent  advantages." 

CLOTH  AND  WARP  DRYING  MACHINES:  Except  in  details,  the  process 
of  draining  drying  machines  of  both  vertical  and  horizontal  types  is  the 
same  as  for  slashers. 

Each  cylinder  is  provided  with  troughs  or  buckets  which,  as  the  cylinder 
revolves,  empty  through  a  pipe  to  a  hollow  shaft  and  through  the  journal 
to  the  return  duct. 


Air  Vent  open  to  Atmosphere 

J°L 


Connect  to  Hot  Well,  or  Drain  independently 


Fig.  17-2.     Application  of  the  Webster  Apparatus  to  a  vertical  drying  machine 

A.  Solid  copper  gasket  inserted  between  bracket  and  housing.  A  copper  gasket  having  hole  equal 
in  area  to  that  in  the  bracket  must  also  be  placed  between  the  bracket  and  housing  on  the  inlet  side  to 
keep  cylinder  alignment  true.  B.  Gate  valve.  C.  Webster  Dirt  Strainer.  D.  Webster  Return  Trap. 
E.  Webster  Bull's-eye  Sight  Glass 

190 


Fig.  17-3.     Application  of  Webster  Apparatus  to  paper  machines  where  there  are  separate  drips 

for  each  cylinder 

The  housings  of  the  machine  and  the  brackets  supporting  the  cylinders 
are  cored  to  provide  ducts  for  conveying  steam  to  the  cylinders  and  con- 
densation away  from  them.  The  frame  on  one  side  acts  as  a  supply  pipe 
while  that  on  the  other  side  acts  as  a  return.  Steam  at  a  pressure  of  15 
Ib.  per  sq.  in.  or  less  is  admitted  to  the  housing  and  passes  through  the 


WEBSTER  RETURN  TRAP 


WEBSTER  DIRT  STRAINER 
WEBSTER  HEAVY  OUT*  TRAP 


Fig.  17-4.     Application  of  the,  Webster  System  to  a  paper  machine  where  there  is  a  common  return 
line  for  all  cylinders  with  air  removed  separately  from  each  cylinder 


191 


brackets  and  the  journals  to  the  cylinders.  To  prevent  collapse,  vacuum 
breakers  are  installed  in  the  cylinder  heads,  usually  on  the  discharge  end. 

Frequently  it  is  advisable  to  make  two  or  three  separate  steam  supply 
connections  to  each  housing,  as  the  area  of  the  cored  opening  in  housing  is 
too  small  to  convey  the  required  amount  of  steam  without  too  great  a  pres- 
sure drop. 

The  duct  in  the  housing  through  which  the  products  of  condensation 
pass  can  best  be  drained  by  the  use  of  one  or  more  Webster  Heavy-duty 
Traps  provided  with  thermostatically  controlled  air  by-pass. 

PAPER  MACHINES:  Two  types  of  machines  of  particular  interest  are 
used  in  the  manufacture  of  paper,  cylinder  machines  and  Fourdrinier 
machines.  Both  require  the  evaporation  of  large  quantities  of  water  from 
the  paper  after  the  pulp  has  been  pressed  and  the  web  has  formed. 

After  passing  through  the  presses  the  paper  usually  contains  about  45 
per  cent  of  water.  This  moisture  is  reduced  to  about  5  per  cent,  depending 
upon  the  thickness  of  sheet  and  the  finish  desired,  by  passing  the  paper 
over  a  series  of  drying  cylinders,  the  inside  surfaces  of  which  are  heated  by 
either  exhaust  or  live  steam  at  low  pressure  or  a  combination  of  the  two. 

Usually  the  steam-supply  header 
runs  parallel  with  the  machine,  close 
to  the  floor,  a  hole  being  bored  in  the 
header  and  connected  by  a  pipe  to  the 
cored  journal  on  the  cylinder. 

The  return  header  runs  either 
above  or  below  the  steam  header  and 
has  the  same  kind  of  connections  as 
the  supply. 

The  drying  cylinders  vary  in  size 
and  length.  For  the  purpose  of  re- 
moving the  water,  one  type  of  cylinder 
is  equipped  with  buckets  and  another 
with  what  is  termed  a  siphon  pipe. 
Cylinders  equipped  with  buckets  dis- 
charge the  condensation  only  when 
in  motion,  while  those  equipped  with 


Fig.  17-5.  Method  of  draining  cylinder  of  a 
paper  machine  using  Webster  Return  Trap  and 
Webster  Dirt  Strainer.  These  connections  are 
suitable  for  operation  with  either  vacuum  or  gravity 
discharge 


siphon  pipes  discharge  whenever  water  accumulates,  provided  there  is  suf- 
ficient pressure  in  the  cylinder  or  vacuum  in  the  return  line  to  give  the  neces- 
sary differential. 

The  condensation  per  square  foot  of  exposed  drying  surface  of  the 
cylinders  depends  upon  the  speed  of  operation  and  the  thickness  and  width 
of  the  paper  on  the  cylinders.  The  stock  from  which  the  paper  is  made, 
together  with  the  amount  of  water  extracted  by  the  press  rolls,  also  has  a 
direct  bearing  upon  steam  consumption.  The  condensation  will  average 
about  1^2  lb.  per  sq.  ft.  of  total  roll  surface  and  naturally  is  greatest  at  the 
wet  end  of  the  machine. 

The  drainage  from  the  cylinders  may  be  removed  either  by  gravity  or 
by  means  of  a  vacuum  pump,  whichever  is  desirable. 

Usually  with  the  Webster  System  of  drainage,  a  Webster  Return  Trap 


192 


Fig.  17-6.  Method  of  draining  cylinder  of  a  paper 
machine  using  Webster  Heavy-duty  Trap  and  Web- 
si  IT  Dirt  Strainer 


Fig.  17-7.  Method  of  draining  cylinder  of  paper 
machine  for  gravity  discharge  where  a  water  line 
is  to  be  maintained,  using  Webster  Heavy-duty 
Trap  with  balanced  steam  connection,  Webster 
Dirt  Strainer  and  a  Webster  Return  Trap  for  vent 
discharging  into  dry  returns 


with  its  Webster  Dirt  Strainer  and  bypass  is  provided  for  each  cylinder  as 
shown  in  Figures  17-3  and  17-5.  All  traps  discharge  into  a  main  return 
which  leads  to  the  point  of  disposal,  which  is  a  feed-water  heater  or  hotwell, 
open  to  the  atmosphere  for  the  removal  of  air. 

Webster  Heavy-duty  Traps  are  sometimes  used  instead  of  Webster 
Return  Traps  (Figure  17-6)  especially  where  the  presence  of  a  water  line  is 
desirable  in  the  return  (See  Figure  17-7). 

The  reader  is  referred  to  Page  184  for  a  complete  discussion  of  the 
selection  of  the  proper  type  of  trap  and  the  precaution  which  should  be 
observed  where  thermostatic  traps  are  used. 


193 


CHAPTER  XVIII 

Application  of  the  Webster  System  to  Railroad 
Terminals  and  Steamship  Piers 

THERE  are  many  uses  for  thermostatically  actuated  return  traps  where 
the  pressures  carried  are  greater  than  in  heating-system  work.    In- 
stances involving  operation  under  steam  gauge  pressures  of  from  15  to 
100  Ib.  are  described  in  this  and  following  chapters. 

The  requirement,  in  all  cases,  is  that  the  return  trap  shall  discharge 
the  water  and  air  of  condensation  without  waste  of  steam  and  that  the  fix- 
ture being  heated  shall  be  maintained  at  maximum  efficiency. 

In  these  special  installations,  certain  fundamentals  must  be  observed 
to  secure  successful  operation.  The  first  requires  that  the  thermostatically 
actuated  traps  must  discharge  directly  to  the  atmosphere  or  to  a  return  line  in 
which  atmospheric  pressure  is  maintained. 

This  latter  condition  may  be  obtained  by  venting  the  return  line  free 
to  the  atmosphere.  In  some  cases  the  same  result  is  secured  by  discharging 
the  returns  into  a  flash  tank,  the  vent  of  which  is  connected  to  the  low-pres- 
sure heating  main,  while  the  condensation  is  cared  for  through  the  usual 
type  of  return  traps  to  the  vacuum  return. 

RAILROAD  TERMINALS — One  of  the  greatest  causes  of  delay  in  the  daily 
movement  of  hundreds  of  trains  into  and  out  of  terminals  where  there  is 
freezing  weather  is  the  difficulty  in  keeping  switches  clear  of  snow  and  ice. 

Many  terminals  have  therefore  adopted  the  method  (Figure  18-1)  of 
placing  steam-heating  coils  between  the  ties,  under  the  switches.  Due  to 
the  unusual  exposure,  these  coils  and  their  supply  lines  are  operated  under 
60  to  80-lb.  gauge  pressure  in  order  to  prevent  freezing.  The  dripping  of 


WEBSTER  HIGH  PRESSURE 
SYLPHON  TRAP 


Sheet  Steel  fastened 
to  Top  and  End  of  Ties 


Fig.  18-1.     Steam  coil  arrangement  for  prevention  of  freezing  of  railroad  switches 

194 


WEBSTER  HIGH  PRESSURE 
SYLPHON  TRAP 


these  lines  and  coils  pre- 
sents a  double  problem: 
First,  water  and  air  of  con- 
densation must  be  freely 
discharged  onto  the  road- 
bed, and  Second,  condensa- 
tion must  not  form  steam 
clouds  that  might  obscure 
nearby  switch  signals. 

A  type  of  thermostat- 
ically actuated  return  trap 
which  answers  these  re- 
quirements has  been  devel- 
oped by  Warren  Webster  & 
Company  after  many  tests 
and  experiments.  This  re- 
turn trap  is  fitted  with 
Monel-metal  seats  and  valve 
pieces  to  withstand  the  wire- 
drawing effects  of  steam  at 
high  pressure  differential. 
The  thermostatic  member 

Fig.  18-2.     Method  for  prevention  of  freezing  of  fire  protection    is   placed    On   the   Outboard 
lines.    The  water  and  steam  pipes  are  encased  in  the  same  insula-  ntmnsnhprir   siHp   nf  thp 

tion  and  the  steam  pipe  is  drained  by  a  thermostatic  return  trap 

trap,  and  as  the  trap  is 

generally  placed  in  the  rock  ballast  of  the  road  bed,  its  exterior  is  usually 
given  a  special  finish  to  give  it  protection  against  the  elements.  (See  Page  275.) 

Railroad  terminals  are  also  equipped  with  extensive  systems  of  water 
lines  for  fire  protection  purposes  and  these  lines,  too,  must  be  kept  from 
freezing.  The  method  of  prevention  (Figure  18-2)  found  most  satisfactory 
is  to  run  a  steam  line,  carrying  from  60  to  80-lb.  gauge  pressure,  parallel 
with  and  close  enough  to  each  water  line  that  both  steam  and  water  lines 
can  be  encased  in  the  same  insulating  covering.  Where  the  water  lines 
terminate,  as  at  hydrant  and  hose  gate  outlets,  the  same  dripping  of  the 
steam  lines  and  the  same  thorough  removal  of  condensation  with  absence  of 
steam  cloud  are  required  as  with  the  yard  switches. 

The  same  type  of  return  trap  is  used  in  both  cases. 

STEAMSHIP  PIERS:  Steamship  piers  in  cold  climates  are  somewhat 
similar  to  railroad  terminals  in  that  the  fire  lines  must  be  protected.  In  ad- 
dition, heat  is  required  for  a  large  number  of  small  enclosures  scattered 
throughout  for  housing  the  pier  clerks. 

Piers  are  so  built  that  water  of  condensation  from  coils  heating  water 
lines  and  clerk  houses  cannot  be  easily  returned.  The  practice  is  to  dis- 
charge the  condensation  overboard  through  the  pier  deck.  The  return  traps 
must,  therefore,  keep  the  lines  clear  of  condensation  to  avoid  possibility  of 
freezing  and  at  the  same  time  avoid  waste  of  uncondensed  steam. 

Webster  Return  Traps  of  similar  construction  to  those  previously 
described  for  railroad  terminals  are  successfully  used  for  this  wori 

195 


CHAPTER  XIX 

:  **.' 

Applications  of  the  Webster  System  to  Vacuum 
Pans  and  Similar  Apparatus 

IN  processes  of  manufacture  where  boiling  of  the  product  at  a  low 
temperature  is  desirable,  a  special  application  of  the  Webster  System 
has  been  devised  for  removing  air  and  water  of  condensation. 

One  of  the  important  uses  for  vacuum  pans  is  in  the  milk-condensing 
industry  and  in  the  following  pages  this  particular  application  of  the  Webster 
System  is  discussed.  However,  the  principles  and  the  Webster  apparatus 
are  equally  applicable  to  other  processes  such,  for  instance,  as  the  manu- 
facture of  sugar,  salt,  candy  or  tartaric  acid. 

The  development  and  growth  of  the  milk  industry  has  reached  a  point 
in  the  last  few  years  where  it  is  now  necessary,  due  to  keen  competition,  to 
use  not  only  the  most  modern  and  efficient  machinery  in  the  process  of  milk 
treatment,  but  to  install  modern  power  equipment  and  a  perfect  system 
of  steam  circulation  in  order  to  insure  the  commercial  efficiency  of  the  plant. 
It  is  essential  that  each  pound  of  steam  (live  or  exhaust)  shall  do  the 
maximum  of  useful  work  and  that  all  water  of  condensation  shall  be  returned 
to  the  boiler. 

There  are  numerous  uses  for  exhaust  steam  in  the  modern  condensory, 
such  as  heating  of  boiler  feed  water,  heating  of  water  for  general  use  and  in 
the  heating  system  of  the  building,  but  as  a  rule  these  require  only  a  small 
portion  of  the  amount  of  steam  available  from  the  exhausts  of  the  engine, 
compressors,  pumps,  etc. 

In  a  condensory  of  say  100,000-lb.  capacity  of  milk  daily,  there  will  be 
available  at  least  200  hp.  of  exhaust  steam,  not  over  20  per  cent  of  which  is 
required  for  any  of  the  above  uses.  The  remaining  160  hp.  of  exhaust  steam 
is  available  for  use  in  the  vacuum  pans. 

The  usual  practice  in  the  past  has  been  to  use  live  steam  in  the  heating 
coils  of  the  vacuum  pan  at  a  pressure  of  about  15  to  20-lb.  gauge,  reducing 
to  this  pressure  from  the  high-pressure  mains.  Very  often  excess  exhaust 
steam  from  the  engines  has  been  wasted  to  the  atmosphere,  being  considered 
a  by-product  of  the  engine  room  with  little  value  excepting  for  its  uses  in  the 
boiler  room.  Exhaust  steam  at  5-lb.  gauge  pressure  contains  about  88  per 
cent  of  the  heat  content  of  the  live  steam  used  to  develop  power  and  is  as 
effective  in  the  vacuum  pan  coils  as  live  steam  reduced  to  the  same  pressure. 
To  make  use  of  exhaust  steam  at  5-lb.  gauge  pressure  where  live  steam 
was  used  in  the  vacuum-pan  coils,  only  slight  changes  are  necessary.  Oc- 
casionally the  sizes  of  coil  connections  must  be  increased  to  the  size  of  the 
coils  themselves  and  where  the  steam  pressure  is  decreased,  a  slight  addi- 
tional amount  of  heating  surface  in  the  coils  will  be  required  on  account  of 
the  lower  temperature  of  the  steam  at  this  pressure.  In  some  plants  where 
exhaust  steam  has  been  substituted  for  live  steam  without  changes  in  the 

196 


Fig.  19-1.     Milk  condenser 

heating  surfaces,  a  slight  additional  time  was  required  to  condense  the  batch 
of  milk.  In  most  cases  this  increase  was  not  more  than  ten  minutes. 

The  usual  control  valve  connections,  that  is,  the  double  globe  valve  and 
a  gauge  attached  to  each  coil  connection,  will  be  the  same  for  use  with  the 
exhaust  steam  as  with  the  live  steam. 

The  return  connections  for  use  with  the  exhaust  steam  are  very  simple. 
A  single  Webster  High-differential  Heavy-duty  Trap  (see  page  249,  Chapter 

197 


24),  with  a  bypass,  is  connected  to  each  coil  outlet.  These  traps  discharge 
to  the  return  main  leading  to  a  vacuum  pump  in  the  boiler  room.  It  is 
essential  that  each  coil  shall  be  drained  separately  into  the  vacuum  return 
main  in  order  that  the  pan  operator  may  have  absolute  control  of  the  steam 
pressure  in  each  individual  coil. 

It  is  necessary  when  condensing  milk  to  vary  the  pressure  in  these  coils 
at  will.  In  some  instances  the  pressure  in  certain  coils  must  be  reduced  to 
atmosphere,  while  the  pressure  in  other  coils  is  increased  to  as  much  as  5 
Ib.  per  square  inch  in  order  to  cause  a  positive  circulation  of  milk  within  the 
pan.  Without  this  positive  control  of  circulation  it  is  impossible  for  the 
pan  operator  to  properly  manipulate  the  process. 

It  is  also  imperative  that  the  water  and  air  of  condensation  shall  be  re- 
moved immediately  from  the  coils  of  the  vacuum  pan  and  that  this  shall  be 
accomplished  independently  of  any  conditions  which  may  affect  the  opera- 
tion of  the  general  exhaust  steam  system  in  the  plant. 

It  is  advisable  to  use  an  independent  pump  and  return  line  for  the  vacu- 
um pans  and  not  to  depend  upon  other  similar  equipment  which  may  be 
used  for  heating  the  building.  The  return  line  should  have  a  gradual  gravity 
pitch  to  the  vacuum  pump  and  should  be  so  arranged  with  by-passes  and 
valves  that  in  case  the  vacuum  pump  should  become  inoperative  for  any 
reason  the  return  condensation  may  be  discharged  by  gravity.  There  must 
necessarily  be  no  pockets  of  any  nature  in  this  return  line. 

A  maintained  vacuum  of  6  to  8  in.  at  the  outlet  of  the  trap  is  usually 
sufficient  to  insure  at  all  times  a  positive  circulation  of  steam  and  the  in- 
stant removal  of  all  water  and  air  of  condensation. 

Not  only  are  much  better  results  obtained  by  the  certainty  of  this  cir- 
culation, but  in  many  cases  where  exhaust  steam  has  been  substituted  for 
live  steam  in  the  milk-condensing  process,  a  marked  improvement  in  flavor 
of  the  product  has  been  noted. 

The  great  saving  in  steam  consumption  in  a  condensory  when  equipped 
with  the  Webster  System  will  usually  pay  for  the  entire  installation  within 
a  few  months.  However,  a  careful  analysis  must  be  made  of  the  existing 
conditions  of  an  old  plant  or  the  requirements  of  a  new  condensory  before 
any  exact  arrangement  can  be  determined.  There  is  no  other  single  im- 
provement to  a  condensory  that  will  approach  the  saving  obtainable  through 
the  economical  use  of  exhaust  steam. 

Figure  19-2  shows  an  older  type  of  connection  for  vacuum'' pans,  in 
which  high-pressure  steam  only  is  used.  The  pressure  is  reduced  from 
125-lb.  per  sq.  in.  boiler  pressure  to  15  or  20-lb.  per  sq.  in.  for  use  in  the  pan. 
The  outlet  connections  are  pipes  without  valves  or  checks,  leading  to  a 
header  which  is  piped  to  a  tank  located  beneath  the  pan.  The  tank  is  a 
receptacle  for  water  and  air  of  condensation.  The  air  is  vented  through 
the  small  vent  valve  while  the  water  is  drained  to  a  high-pressure  positive 
return  trap  which  discharges  the  water  to  an  open  hotwell  or  to  a  feed- 
water  heater. 

The  difficulties  encountered  in  this  construction  will  be  short-circuiting 
of  the  steam  from  one  return  to  the  other  and  the  impossibility  of  maintain- 
ing independent  or  separate  pressure  control  on  each  coil  in  the  pan. 

198 


Fes-sure- reducing  Valve 


To  Boiler  Room 


Fig.  19-2.     Drainage  system  for  a  vacuum  pan  using  a  positive  return  trap 
and  receiving  tank 


The  system  of  piping,  however,  is  in  common  use  in  most  of  the  smaller 
condensories  at  the  present  time. 

Figure  19-3  shows  another  construction  where  the  inlet  connections  are 
similar  to  those  in  Figure  19-2,  but  where  the  outlet  connections  are  con- 
trolled by  means  of  gate  valves  and  check  valves  which  discharge  into  a 
common  return  line.  This  return  line  is  run  direct  to  a  pump  and  receiver 
which  discharges  the  water  back  to  the  boiler.  A  great  many  installations 
are  somewhat  similar  to  this  and  it  is  evident  that  there  is  a  great  deal  of 


199 


waste  of  steam  due  to  the  inability  of  the  operator  to  properly  throttle  the 
controlling  valves  on  the  outlet  connections. 

Figure  19-4  shows  the  approved  application  of  the  Webster  System. 

The  exhaust-steam  piping  includes  a  Webster  Steam  and  Oil  Separator 
and  an  auxiliary  connection  from  the  high-pressure  main  with  pressure- 
reducing  valve.  It  is  essential  that  the  pressure-reducing  valve  shall  be  of 
such  construction  that  it  will  maintain  constantly  the  pressure  which  is  de- 
sired when  it  is  necessary  to  use  live  steam  for  condensing.  The  back- 
pressure valve  must  be  of  such  construction  that  it  is  impossible  at  any  time 
to  exceed  10  Ib.  per  sq.  in.  pressure  on  the  low-pressure  mains. 

The  outlet  connections  from  the  vacuum  pan  are  run  direct  to  the 


Pressure. reducing  Valve 


Fig.  19-3.     Drainage  system  for  a  vacuum  pan  using  a  pump  and  receiver 

200 


Eihaust  Head 


Pressure-reducing  Valve  Back-pressure  Valve         • 

Vilve 

& 


Return  to  Vacuum  Pump 


Drip  to  Waste 


Fig.  19- 1.     Approved  manner  of  applying  the  Webster  System  to  a  vacuum  pan 

Webster  High-differential  Heavy-duty  Traps,  which  are  provided  with  by- 
passes and  thermostatically  controlled  air  lines  and  are  connected  directly 
to  the  vacuum  return  line,  which  is  run  through  a  Webster  Suction  Strainer 
to  the  vacuum  pump.  These  outlet  connections  also  must  be  equipped  with 
small  try-cocks  in  order  that  the  operator  may  test  the  working  condition 
of  any  coil  in  the  pan  at  any  time. 


201 


CHAPTER  XX 


Application  of  the  Webster  System  to  Sterilizers, 
Cooking  Kettles  and  Similar  Apparatus 


H 


OSPITAL  EQUIPMENT:  All  hospital  equipment,  such  as  sterilizers  for 
surgical  instruments,  bandages  and  dressings,  blanket  warmers,  etc., 
requires  steam  at  more  than  the  usual  heating  pressures.  As  these 
fixtures  are  comparatively  small  consumers  of  steam,  being  operated  at  gauge 
pressures  of  15  to  100  lb.,  and  as  they  are  situated  at  different  parts  of 
the  building,  it  is  usual  to  run  a  special  set  of  steam  supply  and  return  lines 
for  them  so  that  steam  may  be  available  at  any  time  throughout  the  year. 
For  the  purpose  of  insuring  rapid  removal  of  condensation  and  air  from 
each  fixture,  a  Webster  Return  Trap  of  similar  construction  to  those 
described  in  the  preceding  chapter  is  placed  on  the  return  of  each  unit.  The 
operating  temperature  of  the  thermostatic  members  of  these  traps  is  close 
to  that  of  steam  at  atmospheric  pressure;  hence  it  is  necessary  to  provide 
sufficient  exposed  piping  between  the  fixture  and  the  trap  to  allow  the  con- 
densation to  cool  down  to  the  operating  temperature  of  the  return  trap. 
This  exposed  piping  is  termed  cooling  surface. 


Dressing  Sterilizer 


Blanket  Warmer  Closet 


Instrument  Sterilizer 


WEBSTER  HIGH 

PRESSURE 
SYLPHON  TRAPS- 


Uncovered  Pipe7 


Floor 


Coupling^! 


Gate 

Vjlvc 


'W. 


Check  Valve 


Uncovered  Pipe 


WEBSTER  HIGH 

PRESSURE       , 
SYLPHON  TRAP , 


Check  Valve 


-  Gate  Valves 
To  Waste  or  Atmosphere 
"Dirt  Pocket 
WEBSTER  HEAVY  DUTY  TRAP 

Fig.  20-1.     Application  of  the  Webster  System  to  instrument  sterilizer,  dressing  sterilizer  and  blanket 

warmer  closet  in  a  hospital 
202 


Vent  lo  Heal  Main 
or  Atmosphere 


High  Pressure  Drip 


WEBSTER  HIGH-PRESSURE 
SYLPHON  TRAP 


Fig.  20-3.  Connections  for  return  Imp 
where  the  operating  pressure  exceeds  10  Ib. 
per  sq.  in. 


Din  Pocket 
High  Pressure  Trap 

Fig.  20-2.  Method  of  discharging  high-pres- 
sure drips  or  returns  from  high-pressure  apparatus 
into  low-pressure  heating  mains  and  vacuum  return 
mains  through  a  Webster  Heavy-duty  Trap 

Each  return  from  trap  before  connecting  into  the  common  discharge 
line  of  similar  traps  should  have  a  check  valve  between  the  trap  and  the 
return  as  well  as  a  hand  shut-off  valve  between  fixture  and  trap  as  shown  in 
Figures  20-3  and  20-4.  This  is  very  important  as  a  protection  for  the  trap 
against  water  hammer. 

Where  several  Webster  High-pressure  Sylphon  Traps  discharge  their 
condensation  into  a  common  return  line,  it  is  necessary  that  this  line 
shall  be  vented  free  to  the  atmosphere,  or  in  cases  where  possible,  to 
the  low-pressure  heat  main  (Figure  20-2).  It  is  important  that  no  back 
pressure  shall  be  carried  on  this  return  line.  In  no  case  should  the  discharge 
of  these  traps  be  connected  directly  to  a  vacuum  return  as  the  vacuum 

Coffee  Urns 


Vent  to  Low  Pressure  Heat 
Main  or  Atmosphere 


To  Return 


Gale  Valves 

To  Waste  or  Atmosphere 
Dirt  Pocket 

'WEBSTER  HEAVY  DUIY  TRAP 
Fig.  20- 1.     Application  of  the  Webster  System  to  kitchen  equipment 

203 


would  unbalance  the  operating  member  of  the  trap  and  cause  it  to  give 
unsatisfactory  results. 

COOKING  KETTLES,  PLATE  WARMERS,  BAIN-MARIES,  COFFEE  URNS 
AND  OTHER  KITCHEN  EQUIPMENT:  This  equipment  requires  practically 
the  same  treatment  as  that  of  hospitals,  and  the  same  general  statement 
about  arrangement  of  return  lines  applies. 

In  food-product  factories  where  the  cooking  equipment  is  much  more 
extensive,  a  special  form  of  float-controlled  return  trap  with  thermostatic 
trap  in  air  line  is  used.  This  particular  type  is  called  the  Webster  High- 
differential  Heavy-duty  Trap.  For  details  of  these  traps  see  Chapter  24, 
page  249.  These  traps  are  also  used  for  removing  the  condensation  and 
air  from  the  steam  coils  of  vacuum  pans  in  evaporating  processes  for 
sugar,  milk,  salt,  tartaric  acid,  candy,  and  the  like. 

It  is  important  in  all  applications  to  high-pressure  duly  that  the  maximum 
initial  steam  pressure  to  which  the  trap  may  be  subjected  does  not  exceed  the 
allowable  pressure  of  that  class  (see  Page  275),  and  that  the  maximum  conden- 
sation rate  shall  be  known.  It  is  also  important  to  know  in  advance  the  lowest 
pressure  to  which  the  vent  of  the  Heavy-duty  Trap  will  be  subjected  at  times,  as 
the  influence  of  this  pressure  is  marked  in  limiting  the  rating  of  the  Webster 
High-pressure  Sylphon  Trap. 


204 


CHAPTER  XXI 

Applications  of  Webster  Systems  to  Greenhouses 

THE  heating  of  greenhouses  is  a  special  field,  owing  to  the  peculiar 
characteristics  of  the  buildings  and  the  necessity  for  uniform  interior 
temperatures. 

Commercial  greenhouses  are  more  exacting  in  their  heat  requirements 
than  are  public  or  private  conservatories.  Constant  maintenance  of  the 
most  desirable  temperatures  is  essential  in  commercial  houses  to  bring  the 
crop  to  salable  maturity  in  the  shortest  possible  time  and  to  keep  the  quan- 
tity of  first-class  product  at  a  maximum  throughout  the  season.  A  single 
serious  temperature  drop  for  a  comparatively  short  interval  may  stunt  the 
crop  beyond  recovery  to  normal  condition  within  a  month's  time,  and  even 
slight  temperature  variation  renders  some  kinds  of  plants  more  susceptible 
to  certain  destructive  fungi. 

The  heat  regulation  should  be  flexible  to  such  extent  that  by  applying 
more  or  less  heat  to  compensate  for  loss  of  sunlight  in  cloudy  weather,  the 
crop  can  be  retarded  or  forced  to  reach  maturity  at  the  time  of  the  most 
profitable  market.  The  blossoming  of  Easter  lilies,  for  instance,  requires 
absolute  regulation  within  a  period  of  a  very  few  days,  and  failure  to 
meet  the  time  limits  results  in  an  almost  total  loss.  The  same  principle  is 
utilized  during  the  period  of  uncertain  sunshine  between  November  and 
February  to  keep  the  daily  production  of  the  majority  of  varieties  of  cut 
flowers  more  uniform. 


—  itfir  •   . 

jLiJ  LLJ  Jjmu 


.  21-1.     Conservatory  of  the  Missouri  Botanical  Gardens 
205 


Owing  to  the  high  rate  of  heat  transmission  through  the  glass  of  which 
greenhouse  enclosures  are  constructed,  the  heating  system  must  be  capable  of 
quick  response  to  the  demands  for  extra  heat  during  nights,  cloudy  and  cold 
days,  and  particularly  when  a  sudden  cold  wind  springs  up.  Co-operating 
with  the  ventilators,  the  heating  system  must  respond  quickly  to  the 
demand  for  less  artificial  heat,  when  the  heat  from  the  sun's  rays  tends  to 
increase  the  interior  temperature  beyond  the  point  desired. 

Until  a  few  years  ago,  hot  water  was  con- 
sidered the  best  medium  for  circulation  in  the 
heating  coils  of  greenhouses.  However,  as  the 
size  and  importance  of  greenhouses  have  in- 
creased, a  medium  with  quicker  response  in 
heat  flow  has  become  necessary  to  better  meet 
the  many  changes  in  outside  temperature  and 
direction  and  velocity  of  wind.  Steam  has 
proved  ideal  for  this  work  where  the  condi- 
tions of  the  individual  problem  have  been 
carefully  analyzed  and  a  suitable  heating  lay- 
out has  been  applied. 

In  different  types  of  greenhouses  the  ar- 
rangement of  the  heating  coils  varies  to  suit  the 
particular  plants  or  vegetables  grown  and  to 
meet  the  needs  of  forcing,  propagation,  etc. 

The  conservatory  group  of  the  Missouri 
Botanical  Garden  at  St.  Louis,  Mo.,  consisting 
of  palm,  economic,  cycad,  succulent  and  fern 
houses  (Figures  21-1  to  21-5),  is  heated  by  the 
Webster  Vacuum  System  of  Steam  Heating. 
These  greenhouses  are  part  of  the  125-acre 
botanical  garden  presented  to  the  public 


UNDER  BENCH 


li-1  Vj  PIPE  COILS 


HOUSE    A 


15-1V4  PIPE  COtLS 


HOUSE     B 


Fig.  21-2.    Plan  of  half  the  Conservatory  of  the  Missouri  Botanical  Gardens,  showing  layout  of  heating  coils 

206 


by  Mr.  Henry  Shaw  at  his  death  in  1889. 
Eleven  thousand  species  of  plants 
grow  in  this  garden.  The  palm  house 
contains  150  kinds  of  palms,  such  as  date, 
cocoanut,  sugar,  Panama  and  rattan.  The 
economic  house  has  a  variety  of  tropical 
and  sub-tropical  plants,  such  as  rubber, 
spices,  drugs,  dyes  and  coffee.  The  cycad 
house  is  arranged  in  Japanese  style  and 
contains  representatives  of  all  known 


Is 
/ 


1  ',\  WPt  COILS 


q 


Fig.  21-.J.    Elevation  of  half  of  houses  A  and  B  (see  Fig.  21-2),  Conservatory,  Missouri  Botanical  Gardens. 
Other  halves  of  these  houses  are  symmetrical  with  the  parts  shown 

207 


Fig.  21-4.     Fern  House  of  the  Missouri  Botanical  Gardens 


prime 


Fig.  21-5.     Floral  Display  House  of  the  Missouri  Botanical  Gardens  during  chrysanthemum  show 
The  accurate  temperature  regulation  obtainable  with  the  Webster  System  greatly  lengthens  the 
life  of  the  individual  blossoms,  thereby  assisting  in  prolonging  the  duration  of  the  show 


208 


genera  of  cycads,  as  well  as  a  collection  of  tropical  evergreens.  The  succulent 
house  contains  species  of  all  the  plants  found  in  the  deserts  of  the  world. 
The  fern  house  has  a  very  complete  collection  of  the  numerous  ferns  and 
their  allies. 

Different  atmospheric  conditions  are  required  in  each  of  these  houses. 
I'Vrns,  for  instance,  would  not  live  in  the  dry  air  needed  by  the  cacti.  The 
Webster  System  is  maintaining  the  required  temperatures  throughout  every 
part  of  these  conservatories,  and  in  most  locations  the  permissible  variation 
in  temperature  is  limited  to  five  degrees. 

The  palm  house  is  60  ft.  high.  To  assure  maintenance  of  tempera- 
ture within  5  deg.  variation,  the  sizing,  locating  and  controlling  of  radiating 
surfaces  were  specially  important  problems  of  the  design. 


Fig.  21-6.    Typical  temperature  chart  from  one  of  the  greenhouses  of  the  Davis  Gardens,  Terre  Haute,  Ind. 

The  outside  temperature  on  the  day  the  chart  was  taken  averaged  28  dog.  fahr.    The  variation 

in  inside  temperature  was  less  than  3  deg.  in  24  hours 

209 


Fig.  21-7.     One  of  the  ten  600  by  80-ft.  greenhouses  of  the  Davis  Gardens,  Terre  Haute,  Ind. 
In  the  trade,  this  establishment  is  looked  upon  as  a  leader  in  quality  of  product  as  well  as  capacity. 
The  ability  to  force  or  retard  the  crop  in  each  greenhouse  assists  materially  in  regulating  the  output  to 
best  meet  demand,  and  in  this  respect  the  Webster  Vacuum  System  plays  an  important  part. 


d 
,-, 


.  ••• 


'*•' 


Fig.  21-8.     Crosswise  view  at  the  center  of  one  of  the  cucumber  houses  of  the  Davis  Gardens, 
showing  arrangement  of  heating  coils  around  the  beds 

210 


Fig.  21-9.     Part  of  the  power  plant  of  the  Davis  Gardens,  showing  the  feed-water  heater  and 
vacuum  pumps  of  the  Webster  Heating  System 

The  heating  coils  are  banked  on  the  side  walls  of  the  houses  as  shown 
in  Figure  21-3,  and  the  arrangement  of  the  coils  is  shown  in  plan,  Figure 
21-2.  Steam  is  supplied  from  a  central  heating  plant  under  pressure  and  is 
reduced  at  the  conservatory,  the  heating  system  operating  at  from  1  to 
2-lb.  gauge  pressure.  The  returns  flow  to  the  power  house,  where  the  main 
vacuum  pumps  discharge  the  condensation  to  an  open  tank,  from  which  it 
is  pumped  to  the  boilers. 

The  J.  W.  Davis  Company  of  Terre  Haute,  Indiana,  operates  the 
largest  hothouse  vegetable  growing  plant  in  the  country,  this  plant  con- 
sist ing  of  10  greenhouses,  each  600  ft.  long  by  80  ft.  wide  and  one  green- 
house, 200  ft.  long  by  20  ft.  wide.  Some  idea  of  the  magnitude  of  these 
houses  may  be  obtained  from  the  fact  that  for  heating  alone  an  1800-hp. 
steam  generating  plant  and  60  miles  of  coils  and  piping  are  required. 

The  main  vegetables  grown  by  the  Davis  Company  are  hothouse- 
grown  encumbers,  tomatoes  and  mushrooms.  The  average  output  is  as 
follows:  cucumbers,  12000  dozen  per  week;  tomatoes,  40000  pounds  per 

211 


212 


Fig.  21-11.     View  across  Orangerie,  du  Pont  Horticultural  Group,  Mendenhall,  Pa. 


Fig.  21-12.     Method  of  heating  for  growing  vines  on  the  walls  of  the  duPont  orangerie.    Air  enters  the 
openings  at  the  bottom  of  the  wall,  is  heated  in  passing  over  the  coils  at  the  top  and  passes  into  the 
rooms.    The  registers  in  the  floor  distribute  heated  air  from  the  indirect  heating  system 

213 


week;  mushrooms,  2000  pounds  per  week.  The  output  includes  also  flower- 
ing plants,  among  which  are  hundreds  of  thousands  of  cyclamen,  grown  for 
the  sale  of  cut  flowers  as  well  as  the  plants  themselves. 

The  temperature  requirements  of  these  greenhouses  are  even  more 
exacting  than  those  of  the  Missouri  Botanical  Garden,  as  shown  by  the 
chart,  Figure  21-6,  taken  from  the  recording  thermometer. 

The  steam  for  heating  is  taken  from  a  95-lb.  steam  line  running  through 
the  connecting  corridors,  and  the  pressure  is  reduced  in  each  greenhouse  for 
the  Webster  Vacuum  Heating  System,  which  operates  at  5-lb.  pressure. 
The  condensation  is  carried  through  a  vacuum  return  back  to  the  power 
plant,  where  it  is  delivered  by  the  main  vacuum  pumps  through  a  tank  to 
a  Webster  Feed-water  Heater  and  from  there  pumped  to  the  boilers. 

The  Horticultural  Group  (Figure  21-10)  on  the  private  estate  of  Mr. 
Pierre  S.  du  Pont  near  Mendenhall  Pa.,  is  heated  by  the  Webster  System. 

The  main  buildings  comprise  the  orangerie,  exhibition  hall,  peach 
houses  and  display  houses.  The  orangerie  is  approximately  80  by  180  ft. 
and  the  exhibition  hall  is  about  80  by  110  ft.  The  two  peach  houses  lie  on 
either  side  of  the  orangerie  and  are  approximately  50  by  100  ft.  in  length, 
with  the  display  house  30  by  50  ft.  at  the  extreme  ends.  At  the  rear  of 
the  Exhibition  Hall  is  a  stage,  or  rather  a  veranda,  to  the  future  building, 
which  will  eventually  be  the  casino.  At  this  end  of  the  building  are  located 
the  organ  and  service  rooms  for  entertaining  purposes. 

The  heating  for  this  group  is  remarkable  in  that  the  main  buildings 
are  heated  by  a  system  of  indirect  radiation  with  a  gravity  circulation  of  air. 
The  indirect  surfaces  enclosed  with  copper  casings  and  pans,  are  placed  in 
a  series  of  tunnels  which  lie  under  the  walk-ways.  Fresh  air  when  required 
is  taken  through  two  sets  of  primary  heaters  located  in  the  orangerie  and 
one  set  of  primary  heaters  for  each  of  the  peach  and  display-house  wings. 
These  are  furnished  with  sufficient  surface  to  maintain  the  air  in  the  tunnels 
at  60  deg.  fahr. 


214 


CHAPTER  XXII 


M 


Installation  Details 

"ANY  of  the  methods  of  pipe  connections  which  have  been  developed 
by  Warren  Webster  &  Company  during  the  past  34  years,  and 
have  become  standard  practice,  are  shown  in  this  chapter  and 
elsewhere  in  connection  with  descriptions  of  specific  apparatus.  Most 
of  the  illustrations  have  been  published  as  Webster  Service  Details  and  are 
familiar  to  the  profession  and  trade.  These  drawings,  which  indicate  the 
general  arrangement  of  the  pipe,  fittings  and  Webster  apparatus  have 
been  revised  from  time  to  time  and,  as  shown  here,  represent  the  latest  and 
best  thought.  They  are  not  to  be  used  for  exact  layouts  of  piping,  as  each 
individual  application  presents  its  own  special  conditions.  No  effort  has 
been  made  to  indicate  the  necessary  unions  or  right  and  left  nipples  required 
for  the  connections,  as  these  requirements  for  any  case  would  naturally 
be  best  determined  by  the  detail  of  the  layout  or  by  the  steamfitter  at  the 
job,  based  upon  his  skill  and  upon  materials  available. 


Details  Applicable  to  Both  the  Webster  Vacuum  System 
and  the  Webster  Modulation  System 


Rise  to  new  level 


Rise  to  new  level 


WEBSTER  CLASS" B 
DIRT  STRAINER, 
Reducing    Gate  Valve 
Flange  /  =^=  / 


Provide  at  least  3-0 
if  pipe  cooling  surfac< 
between  drip  point  and 

return  trap  Connecting 

or  side  of  return  main 


Fig.  22-1.  Application  of  a  Webster  Return  Trap 
on  a  low-pressure  heat  main,  at  a  low  point  where 
the  main  rises.  A  sufficient  length  of  uncovered  pipe 
must  be  provided  between  the  drip  point  and  the 

ri'liirn  trap 


WEBSTER  CLASS  "B" 

DIRT  STRAINER 
Reducing 
Flange 


WEBSTER  HEAVY  DUTY 

Set  trap  on  bracket  suppori 
on  foundation  or  on  floor- 


icct  into 
top  or  side  of 
return  main 


Fig.  22-2.  The  drainage  of  a  low-pressure  heal 
main  at  a  low  point,  where  the  line  rises,  is  of  such 
importance  that  special  attention  is  warranted. 
This  diagram  shows  a  large  main  with  drip  through 
gate  valve,  Webster  Dirt  Strainer  and  Webster 
Heavy-duty  Trap 


215 


By-pass  with  Globe  or  Angle  Valve 


WEBSTER 
WATER  ACCUMULATOR  X 


Tee  for  Gauge  Connection 


Live  Steam  from  Boiler 


Provide  Pet  Cock  for  Venting  Diaphranrr 


Straight  Pattern  Pressure 
Reducing  Valve 

Fig.  22-3.  Connections  for  a  steam  pressure-reducing  valve.  The  control  pipe  from  the  low-pressure 
side  of  the  line  must  be  taken  from  a  point  far  enough  from  the  valve  to  insure  that  the  pressure  will  have 
been  fully  expanded.  The  use  of  the  Webster  Water  Accummulator  (see  Page  267)  facilitates  a  constant 
static  pressure  on  the  diaphragm  of  the  pressure-reducing  valve.  The  pop  safety  valve  prevents  pressure 

building  up,  particularly  at  very  light  loads 
Return  Riser 


Supply  Hi 


Return  Main 


Reducer— —W 


Pipe  uncovered- 


Gate  Valve  - 


Dirt  Pocket — 5 


Fig.  22-4.  Method  of  dripping  supply  risers  Fig.  22-5.  Three  methods  of  making  loops  to 
through  a  Webster  Return  Trap  into  vacuum  return  provide  for  expansion  movement  in  risers.  The  ex- 
line;  the  vertical  leg  acts  both  as  cooling  surface  and  pansion  of  supply  and  return  risers  should  have 
dirt  pocket  careful  study 

Fig.  22-6.     Arrangement 
for  dripping  the  end  of  a  sup- 
ply main,  which  also  carries 
the  condensation  from  the  up- 
WEBSTER  feed  risers,  into  an  overhead 

RETURN  TRAP        return  main.  The  return  trap 
is   located  at   a    point    four 
feet  or  more  from  the  point 
to      dripped 


_  Fig.  22-7.  Arrangement  for  drip- 
ping a  down-feed  riser  into  an  over- 
head return  main,  showing  the  un- 
covered horizontal  cooling  pipe 


WEBSTER 
RETURN  TRAP 


Overhead  Return  Main 
216 


Dirt  Pocket 


Fig.  22-8.  Dripping  the 
heel  of  a  down-feed  supply 
I'i-cr.  where  provision  must 
also  l>e  made  for  down  thrust 
or  expansion.  The  hori/imtal 
pipe  must  pitch  sharply 
enough  to  prevent  formation 
of  pocket  when  the  riser  is 
fully  expanded 


.Floor  Line 


Up  1o  Radiator 


Floor  Line 
/     Jt 


Gale  Valve 


Return  Main  at  Floor 


Fig.  22-9.  The  end  of  an 
up-feed  system  supply  main 
wnere  provision  must  be 
made  for  the  drip  of  the  main 
as  well  as  the  condensation 
from  the  risers.  The  return 
is  located  along  the  floor  and 
the  vertical  line  to  return  trap 
can  be  used  as  a  cooling  leg 


WEBSTER  RETURN  TRAP 


Fig.  22-10.  Arrangement  for  drip- 
ping down-feed  risers  into  an  overhead 
return  line.  Cooling  pipe  used  with  a 
Webster  Dirt  Strainer  located  at  the 
entrance  to  the  return  trap.  The  hori- 
zontal pipe  must  pitch  sharply  down- 
»;ircl  to  prevent  formation  of  pocket 


WEBSTER 
DIRT   STRAINER 

WEBSTER 
RETURN  TRAP 


Fig.  22-11.  Arrange- 
ment for  dripping  the  end 
of  an  overhead  supply 
main  through  Webster 
Dirt  Strainer  and  Return 
Trap  into  an  overhead  re- 
turn main 


217 


Fig.  22-12.  The  drip  of  the  end  of  a 
branch  supply  main  which  also  carries 
the  drip  of  down-feed  risers.  A  Web- 
ster Dirt  Strainer  is  used  in  place  of  a 
dirt  pocket 


WEBSTER 
RETURN  TRAP 


Gate  Valve 


=0= 


Return  Riser    WEBSTER  MODULATION  VALVE 
Supply  RiM_r -Bushmfl 


Water  Pattern 
Radiator 


Use  Drip  Hub 
Section  or 
(Centric  Bustling 

/WEBSTER 
/'    RETURN 
TRAP 


Fig.  22-13.  Showing  provision 
for  expansion  on  a  down-feed 
riser  and  the  method  of  dripping 
through  Webster  Dirt  Strainer 
and  Return  Trap.  Pitch  hori- 
zontal pipe  downward  sharply  to 
prevent  formation  of  pocket 

^  Return  Main  at  Floor 


WEBSTER 
DIRT  STRAINER 


Fig.  22-14.  Arrangement  of 
connections  to  a  hot-water  type 
radiator  where  the  branch  run- 
outs  are  in  the  floor  construction 


Gate  Valve' 


Return  Riser. 


WEBSTER  MODULATION  VALVE 
Floor  Line 


,_Supply 
Riser 


Eccentric 
Bushing 


,Steam  Pattern  Radiator 


Eccentric  Bushing 

WEBSTER  RETURN  TRAP 


Fig.  22-15.     Arrangement  of  connections  to  a  steam-type  radiator  where  the  branch  run-outs 

are  in  the  floor  construction 

218 


Supply  Riser 


Healing 
[User— >. 


(None  of  the  Piping  shown 
on  this  detail  to  be  covered 


Connect  to  Return 


Fig.  22-16.  In  certain  classes  of  buildings  a  small 
amount  of  heating  surface  is  often  desired  in  bath 
rooms,  etc.,  without  involving  the  expense  of  sep- 
arate radiators.  Where  these  rooms  are  one  above 
the  other  a  heating  riser  may  be  used  with  connec- 
tions as  shown  in  this  diagram 


Return  Main 


Fig.  22-17.  The  dripping  of  the  end  of  an  over- 
head steam  supply  main  where  the  return  line  is 
carried  along  near  the  floor.  The  uncovered  ver- 
tical line  to  the  return  trap  acts  as  a  cooling  leg 


Supply  Riser 


WEBSTER  MODULATION  VALVE 
/  Bushing 


Return 
Riser 


Use  Drip  Hub  Section 
or  Eccentric  Bushing 


Fig.  22-18.  Arrangement  of  connections  to  a 
radiator  in  a  factory  or  loft  building  where  there  is 
no  objection  to  branch  run-outs  on  tne  ceiling  of  the 
floor  below 


Q    Return  Riser 

Supply  Riser 

.WEBSTER  MODULATION  VALVE 

\ 

v            Busliing 

1 

HUff 

Mitt' 

".Water 

Pattern 

Radiator 

Use  Drip  Hub 

Section  or 

Eccentric 

ra  i         rp 

• 

Bushing, 

T^  d 

*—  Pitch  ^—  «•     ^  ^1 

M  M     ,^_JRtTLRN 

TRAP 

1 

Fig.  22-19.  Arrangement  of  connections  to  a 
radiator  with  all  branch  run-outs  exposed  in  the 
room 


219 


Supply  Riser 


WEBSTER 
MODULATION  VALVE 


Hour  Line  . 


Eccentric  Bushino 


Fig.  22-20.  Arrangement  for  removing  a  considerable  amount  of  condensation  from  a  down-feed  riser. 
The  drip  goes  through  a  Webster  Dirt  Strainer  and  Return  Trap,  the  connection  to  lowest  radiator  being 
made  above  the  drip  point.  Fig.  24-23,  page  253,  shows  an  alternate  method  using  a  Webster  Double- 
service  Valve 


.-Manifold  Coil 


Above  Method  for  Coils  ^ 
of  not  over  1 0  Pipes 

Hz" Short  Nipple 

Reducing  Tee 
Dirt  Pocket  — 
11,2  Nipple,  6"long 

>/Manifold  Co 


Above  Method  for  Coils 
of  not  over  1 0  Pipes 


Connect  into  Top  c 

Vacuum  Return 
,,0irt  Pocket 
1'/2  Hippie,  6"long 
ushina 


Above  Method  for  Coils ' 
of  1 1  Pipes  or  over 

1'/2  Short  Nipple' 
Reducing  Tee 
„  Dirt  Pocket 
|V2  Nipple,  6"lono 

Fig.  22-21.  Drip  connections  to  the  return  head- 
ers of  manifold  coils.  Coils  of  ten  pipes  or  less  have 
one  return  header  and  those  of  over  ten  pipes  are 
usually  split  and  provided  with  two  headers.  Fig. 
- 1-23,  page  253,  shows  an  alternate  method  using  a 
Webster  Double-service  Valve 


Connect  into  Top 
of  Vacuum  Return 

Fig.  22-22.  Arrangement  of  headers  similar  to 
Fig.  22-21,  but  showing  the  use  of  the  Webster  Dirt 
Strainer  at  the  entrance  of  the  return  traps 


220 


Bottom  Outlet  ManiloU 
WEBSTER   RETURN    TRAP 


PLAN 

BOTTOM  OUTLET  MANIFOLD 


Bottom  Outlet  Manifold 


WEBSTER  RETUBN 
TRAP 


^WEBSTER 
>  DIRT  STRAINED  < 
PLAN 
BOTTOM   OUTLET   MANIFOLD 


Connect  Into  telurn 
main  «r  riser 


Nipple,  maximum  slie. 


hippie,  mliimum  siie 


ELEVATION 

END  OUTLET   MANIFOLD 
Drop  I 


Reducing  Ell, 
bushed  II  neressary 
WEBSTER 
,DIRTSTRAI.ER 


Fig.  22-23.    With  drop  leg  to  catch  dirt 


Fig.  22-24.     With  Webster  Dirt  Strainer 


Return  connection  to  a  flat  overhead  coil  where  (above)  a  bottom-outlet  manifold  and  where  (below) 
an  end-outlet  manifold  is  used.    Dirt  is  collected  by  drop  leg  (Fig.  22-23)  or  by  a  Webster  Dirt  Strainer 

(Fig.  22-24) 


Manifold 
Coil 


Manifold 
Coil 


WEBSTER  RETURN  TRAP     -|$ijP=8ir   Gale  Valve 

ff 

Drop  Leg 

Fig.  22-25.     With  drop  leg  to  catch  dirt 


WEBSTER  CUSS  "B" 
DIRT  STRAINER 


Fig.  22-26.    With  Webster  Dirt  Strainer 


Wide  flat  overhead  coils  should  have  return  connections  taken  from  both  ends  of  the  return  manifold. 
Dirt  is  collected  by  a  drop  leg  (Fig.  22-25)  or  by  a  Webster  Dirt  Strainer  (Fig.  22-26) 


221 


Fig.  22-27.  Arrangement  for  profitable  use  of  the  heat 
in  the  condensation  from  a  heating  system.  The  conden- 
sation is  passed  through  the  coils  of  an  auxiliary  water 
heater  and  its  heat  is  transferred  to  water  for  domestic  or 
manufacturing  use 


NOTE — Additional  details  applicable 
to  the  Webster  Modulation 
System  will  be  found  on 
pages  228  to  232 


Details  Applicable  to  the  Webster  Vacuum  System  Only 


Return  Inlet 


Fig.  22-28.  Under  certain  conditions  the  condensation  from  the  heels  of  down- 
feed  risers  can  be  removed  by  connecting  the  separate  gravity  drip  or  wet-return  line 
to  the  return  inlet  of  a  Webster  Feed-water  Heater.  In  this  instance,  the  static  head 
between  the  top  of  the  heater  and  the  lowest  radiator  connection  must  exceed  the 
pressure  in  the  heater.  Suitable  connection  of  the  return  line  to  the  heater  is  shown 
in  the  diagram 

222 


Return  Riser 


This  Pipe  to  be  same  size 
as  Inlet  to  Trap 


Fig.  22-29.  Where  the  drips  of  risers  and  mains  are  carried  through  a  separate  gravity  drip 
line  near  the  floor  and  it  is  desired  to  deliver  the  condensation  into  an  overhead  vacuum  return 
line  through  a  Webster  Heavy-duty  Trap,  the  arrangement  shown  has  proved  most  satisfactory 


Overhead  Vacuum  Return 
WEBSTER  LIFT  FITTING 


This  Pipe  to  be  same  size 
as  Inlet  to  Trap 


, Floor  Line 


Fig.  22-30.  In  the  usual  down-feed  system  where  the  drips  of  risers  are  cared  for  by  a  separate 
gravity  drip  line  run  near  the  floor  and  where  the  condensation  is  to  be  delivered  to  an  overhead 
vacuum  return  line  through  a  Webster  Heavy-duty  Trap,  the  method  shown  should  be  followed 

223 


WEBSTER  RETURN  TRAP 
Plug 


—  Steam  Supply  Main 


-  Return  Main 


Fig.  22-31.  Arrangement  for  drip- 
ping both  riser  and  main  where  an  up- 
feed  riser  is  fed  from  the  bottom  of  a 
supply  main.  A  vertical  cooling  leg  is 
used 


G| 
* 


Return  Main 


Fig.  22-32.  Arrangement  of  connec- 
tions where  the  up-feed  riser  is  fed  from 
the  top  of  the  overhead  supply  main 
and  the  return  main  is  also  overhead. 
A  vertical  cooling  leg  is  used 


WEBSTER  RETURN  TRAP- 
Plug- 


Supply  Riser 


Floor  Line 


Dirt  Pocket 
Cap 


Ceiling/ 
WEBSTER  RETURN  TRAP 


Return  Main 


Return  Riser 


Gate  Valve 


Supply  Riser 


•—Dirt  Pocket 
i-  -  Cap 


Uncovered  Pipe 
not  less  than  3'fj"long 

Fig.  22-33.    Where  it  is  not  possible  to  run  a  vertical  cooling  leg  on  the  drip  of  the  riser,  cooling  surface 
in  the  form  of  a  horizontal  pipe  may  be  employed  as  shown 

224 


Fig.  22-34.    Arrangement  for  removal  of 
condensation  from  a  group  of  not  over  14 
sections  of  vento  radiation,  where  the  steam 
supply  enters  one  end  of  the  group  and  the 
returns  are  taken  from  the  opposite  end. 
The  return  of  each  group  is  separate,  the  con- 
densation being  carried  through  a  common 
return  line  to  the  Webster  Heavy-duty  Trap, 
and  the  air  from  each  group 
handled  s e  p a r a t e 1 y 
through    a    Webster    Re- 
turn Trap  connecting  to 
a  common  discharge  line 
to  the  vacuum  return  line. 
For  details  of  the  Webster 
Heavy-duty  Trap  see  Fig- 
ure 22-35 
WEBSTER  RETURN  TRAPS 


Blast  Heater  Sections 


Gale  Valve  — 

WEBSTER  DIRT  STRAINER 

WEBSTER  HEAVY  DUTY  TRAP 


Fig.  22-33.     Cross  section  of  Webster  Heavy-duty  Trap  with  thermostatically  controlled  air  by-pass, 

to  prevent  trap  from  becoming  air-bound 

225 


Steam  Supply- 

Connections 


Fig.  22-36.    The  usual  method  for  removal  of  con- 
densation from  a  group  of  not  over  22  sections  of 
vento  radiation  supplied  with  steam  at  each  end,  is  to 
provide  a  drip  connection  also  at  each  end  as  shown. 
In  some  instances,  however,  where  the  pressure  is  low 
or  more  than  22  vento  sections  are  used,  one  of  the 
return  lines  should  be  extended 
through  the  Vento  bushing  and 
to  about  the  center  of  the  group, 
so     that     air-binding     will     be 
avoided 


Steam  Supply 
Connections 


Blast  Heater  Sections 


WEBSTER  .RETURN  TRAPS 


Drip  Connections 
same  as  shown  - 
tor  opposite  Side 


Vacuum  Air  Line 


-  Blast  Heater  Sections 


Eccentric 
Bushing 


Gate  Valve- 

WEBSTER  DIRT  STRAINER > 

WEBSTER  RETURN  TRAP 

WEBSTER  HEAVY  DUTY  TRAP, 


Fig.  22-37.  Method  of  dripping 
double-tier  blast  heater  sections 
through  Webster  Dirt  Strainer  and 
Heavy-duty  Trap 


Vacuum  Air  Line 


Check  Valve 


WEBSTER  DIRT  STRAINER 


226 


\  Uncovered  Pipe 
not  less  than  3  0  long 


Supply  Steam 
Connections 


Return  Main 
WEBSTER  RETURN  TRAP 

Fig.  22-38.     Drip  of  main  and  up-feed  riser  using  horizontal  cooling  surface 

Lock  Shield 
Angle  Valve 


IT] 

1 

r 

Hot  Water  Outlet 
HotWatei  Generator 
Steam  Inlet 


Drip 


'Mud  Blow 


WEBSTER  CLASS  "B"  DIRT  STRAINER 


Blast  Heater  Sections 


Eccentric  Bushings 


WEBSTER  DIRT 
STRAINER 

WEBSTER 
RETURN 
-TRAPS 


Air  Pipe  must  be 
'/2  Diameter  ot  Return 


Plugged  Tee 


Line  of  Trench 
Under  Doorway 


Vacuum  Return 


Fig.  22-39.  Arrangement  of  piping  where 
-Plug  a  vacuum  return  line  is  carried  along  the  wall 
near  the  floor  and  passes  doorways  or  other 
openings.  The  water  is  carried  under  the 
opening  and  the  air  is  passed  through  the 
line  over  the  opening 


Fig.  22-40.     Method  of  dripping  blast  heater  section  through 
Webster  Return  Traps 


WEBSTER  HEAVY-DUTY  TRAP 


Trap  on  Bracket  Support 
on  Foundation  or  on  Floor 


Connect  into 
Vacuum  Return 


Fig.  22-41.  The  approved 
method  of  draining  condensation 
from  the  coils  of  a  hot-water 
service  heater  to  the  vacuum 
return  line  through  gate  valve, 
Webster  Dirt  Strainer  and 
Webster  Heavy-duty  Trap 


227 


Details  Applicable  to  the  Webster  Modulation  System  Only 


Supply  Riser  or 
Supply  Connection 
to  Radiator 


This  Connection '/2  when  Air  Line  Valye  is 
10'  0"or  less  from  Dry  Return  Branch  or 
Main  and  3/J  when  over  1 0' "'distant  / 


Ceilno  Line" 
'/2 WEBSTER  RETURN  TRAP. 

'/2  Socket 


Supply  Main  must  be/ 
Run  Full  Size  to  Drip 
Point  Connection 

Drop  Lea  - 


First  Floor  Line  -^ 


Water  Line  of  Boiler^ 


Overhead  Dry  Reti 

Under  no  Circumstances  must  the 
Center  Line  of  this  Pipe  be  less  than 
6"  above  Center  Line  of  Return  Inlet 
of  Vent  Trap 


Reducing  Tee 


Union  above  Water  Line  of  Boiler 
,  Water  Line  of  Boiler 


Connect  into  Wet- 
Return  Main 


Connection  into  Wet  Return  Line 


Wet  Return  near  Flo 


Wet  Return  near  Flooj 
with  space  beneath  for 
Cleaning 


The  Connection  into  Wet  Return 
must  be  same  size  as  Dry  Return 
before  Rise  is  made 


This  Connection  must  be  on  same 
Centre  as  Wet  Return 


Special  Swing  Check  Valve 


L 


Union  above 
Water  Line 
of  Boiler 


--Floor  Line 


Fig.  22-13.  Where  a  chip  is  retjuiredjat 
the  end  of  a  heating  main,  the  air  should 
usually  be  vented  through  a  Webster  Re- 
turn Trap  into  the  dry  return,  as  shown 
in  this  diagram 


Fig.  22-42.  The  dry  return  in  a  Webster  Modulation 
System,  due  to  its  required  grade,  must  sometimes  get 
down  into  the  head  room,  in  which  event  it  may  be 
drained  into  the  wet  return  and  elevated  to  a  higher 
level.  Certain  fundamentals  must  be  observed  in  do- 
ing this.  The  most  important  is  that  at  the  point 
where  the  change  in  elevation  occurs,  the  dry  return 
must  never  be  closer  than  6  in.  to  the  level  of  the 
inlet  to  the  Webster  Modulation  Vent  Trap 


228 


WEBSTER  RETURN  TRAP 
Above  hiohest  point  of  - 
Dry  Return 


Gate  Valve 


1/2  Air  Line 


^ 


Supply  Main 


Connect  into  Top  of  Return 


30"  or  more  il  possible 


^Return  Line 

Fig.  22-14.  There  is 
often  a  demand  for  hot 
water  for  domestic  sup- 
ply where  this  water 
can  best  be  heated  by 
transfer  of  part  of  the 
heat  from  the  conden- 
sation in  the  steam 
heating  system.  The 

diagram  shows  one  method  of  doing  this  in  connec- 
tion with  a  Webster  Modulation  System.  The  hot- 
water  heater  and  storage  tank  should  be  located  close 
to  i  lir  steam  boiler  so  that  the  steam  supply  will  be 
available  when  the  plant  is  being  operated  nt  very 
low  pressures 


l 

Hot  Water  Generator 

1 

\ 

1 

\ 

\ 

Union ' 


This  Connection  must 
be  on  same  Centre  as 
Wet  Return 


Special  Swing 
Check  Valve 


BE: 


Water  Line  of  Boiler . 


-Return  from  Hot  Water  Generator.  Connect  to  Wet  Return 


Wet  Return  near 


Floors 


floor  Line 


WEBSTER   RETURN   TRAP 


Ceiling  Line    "* 


Radiator 


Close  Nipple' 


Union  above 
Water  Line  of  Boiler 


Connect  into 
Wet  Return  Main 


Never  less  than  30*and 
u  much  more  as  possible 


Grade  Radiator  t'in  lO'O* 
toward  Wet  Return  end 


Supply  Main 


Fig.  22-45.  Connections  for  overhead  radia- 
tion in  basement,  where  there  is  sufficient  drop 
for  gravity  flow  between  the  radiation  and  the 
water  line  of  the  boiler 


Watei  Line  of  Boiler 


Speci 
f^.*  Thi 


ial  Swing  Check  Valve 
This  Connection  must  be  on  same 
center  as  Wet  Return 


Wet  Return  near  Floor 


229 


}l-i   Rod  threaded  at  Ends  with 
;/V'  Pipe  Sleeve  over  Rod  must 
extend  thru    Bolt  Holes  in  Diaphram 
Portion  of  Damper  Regulator 


WEBSTER  MODULATION  VENT  TRAP 


Overhead  Return  from 
Heating  System 


Drip  from  Bottom  of 
Steam  Header,  to 
connect  to  Return 
Header  of  Boiler 


Check  Draft  Door 


Fig.  22-46.    Typical  ap- 
plication of  Webster 
Damper  Regulator 
to  a  cast-iron  sec- 
tional boiler 


Vent  Valve, 


Fig.  22-17.     Method  of  making  connections  to  boilers  operating  in  parallel.      Check  valve  on  vent  dis- 
charge trap  only.     This  is  the  arrangement  of  return  connections  required  by 
many  boiler  insurance  companies 

230 


WEBSTER 
MODULATION  VENT  TRAP 


Overhead  Return 
from  Heating  System 


'/{Rod  Threaded 

— r\      at  ends  with  3/J" 

v>i      Pipe  Sleeve  over 


Rod  must  extend 
through  Bo 
in  Diaphragm  For 
lion  of  Damper 


Drip  from  Bottom 
of  Steam  Header 
o  connect  to  Return 
Header  of  Boiler 


With  thermostatic  control 


'/?  Rod  Threaded  at  ends  with 

3/4  Pipe  Sleeve  over  Rod  must 

eitend  through  Bolt  Holes  in 

Diaphragm  Portion  of  Oami 

Regulator. 

Remove  Pin  from  Damper 

Regulator. 

WEBSTER ! 

MODULATION 

SYSTEM  GAUGE 


Drip  from  Bottom 

of  Steam  Header 

to  Connect  to  Return 

Header  of  Boiler 


Note:- 

Damper  Regulator  Lever  to  Rest  on 

Knife  Edge  in  Slot  of  Damper  Regulator 


With  time-clock  Control 


Fig.  22-18.     Typical  applications  of  special  controlling  devices  which  may  be  applied  to 
Webster  Damper  Regulators 

231 


WEBSTER  RETURN- 
TRAP,  above  Hiohest  l^gr0 M!pf    1/2  Ait  Line 

Point  ol  Dry  Return         [fj|.(;oupling  \\  ^Connect  inlo  Top  ot  Return  ^Supply  Line 


Fig.  22-19.  Radiation  must  sometimes 
be  placed  on  the  side  walls  of  basements, 
where  steam  can  be  circulated  only  by  pro- 
viding sufficient  head  for  gravity  flow  be- 
tween the  radiator  return  outlet  and  the 
water  line  of  the  boiler.  The  arrangement 
shown  handles  this  problem  well 


This  Connection  must 
be  on  same  Center  as 
Wet  Return 

Special  Swing 
Check  Valvei 

THE 


30  or  more  if 
Water  Line  ol  Boiler 


Return  from  Radiator 
Connect  to  Wet  Return 


Wet  Return  near  Floor 


-j- 


Bleeder 


Fluur  Line 


232 


CHAPTER  XXIII 

Capacities  and  Ratings  of  Webster  Valves 

and  Traps 

APACITY  is  a  basis  obtained  from  tests  under  one  set  of  conditions 
|j  from  which  ratings  are  deduced  for  other  operating  conditions. 

The  term  capacity  is  used  in  "Steam  Heating"  to  denote  the 
number  of  pounds  of  condensation  per  hour  (Wi)  which  at  uniform  flow  will 
pass  through  the  specified  apparatus  when  the  pressure  is  maintained  at 
1  Ib.  per  sq.  in.  (Pi)  above  that  of  the  atmosphere  and  the  pressure  at  the 
outlet  is  that  of  the  atmosphere  (P«). 

Having  obtained  the  capacity  of  any  unit  of  steam-heating  apparatus 
under  these  standard  conditions,  ratings  may  be  estimated  within  a  very 
small  error,  for  other  stated  conditions  of  pressure  difference,  time  or 
amount  of  heat  content  in  the  steam  at  given  initial  pressure. 

For  any  other  pressure  difference  (Ps  -  P4)  not  differing  greatly  in 
amount  from  the  standard  pressure  difference  (Pi-  P2),  the  quantity  of 
discharge  (W2)  varies  from  the  quantity  (Wi)  discharged  under  standard 
conditions  in  proportion  to  the  square  roots  of  the  pressure  differences;  that 
is  _ 

W     -  W 


or  so  nearly  as  to  be  within  the  normal  errors  of  test. 

The  distinction  which  should  be  made  between  capacity  and  rating, 
especially  where  rating  is  expressed  in  some  indeterminate  value  like  "square 
feet  of  radiation,"  can  best  be  emphasized  by  examples. 

Assume  a  radiator  trap,  the  capacity  of  which,  with  a  drop  from  1-lb. 
pressure  above  atmospheric  in  the  radiator  and  trap,  to  atmospheric  pressure 
in  the  trap  outlet,  has  been  found  by  tests  to  be  60  Ib.  of  condensation  per  hr. 

Example  1.  At  what  should  this  trap  be  rated  in  square  feet  of  radia- 
tion on  a  coil  in  a  room  of  60-deg.  average  temperature,  when  the  steam 
pressure  in  the  coil  is  4-lb.  gauge  and  the  vacuum  at  the  trap  outlet  is 
10-in.  or  5-lb.  gauge? 

Answer:  The  pressure  difference  through  the  trap  would  then  be  4  +  5, 
or  9  Ib.  The  flow  through  the  trap  would  be  as  the  square  root  of  1  is  to 
the  square  root  of  9,  or  three  times  the  capacity  of  the  trap  at  standard 
1-lb.  pressure  difference.  This  figures  out  180  Ib.  per  hr. 

Each  pound  of  steam  at  4-lb.  gauge  pressure  gives  up  in  condensing  in 
a  coil  about  963  B.t.u.  of  latent  heat,  a  total  of  963  X  180  or  173340  B.t.u. 
per  hr.  Under  the  temperature  due  to  4-lb.  gauge  pressure  the  coil  would 
probably  give  off  324  heat  units  per  sq.  ft.  of  surface.  Therefore,  the 
rating  of  this  trap  under  the  above  conditions  would  be  324  divided  into 
173340,  or  535  sq.  ft.  of  direct  radiation. 

Example  2.     At  what  would  this  same  trap  be  rated  in  square  feet  of 

233 


radiation  on  the  same  kind  of  a  coil  similarly  placed  when  supplied  with  steam 
at  J^-lb.  gauge,  and  exhausting  to  atmospheric  pressure  at  the  outlet? 

Answer:  The  pressure  difference  through  trap  being  as  stated,  }/±  Ib. 
per  sq.  in.,  the  flow  through  trap  will  be  as  the  square  root  of  1  is  to  the  square 
root  of  J4,  or  ^  the  rate  at  1-lb.  difference  in  pressure,  or  30  Ib.  of  steam  per 
hr.  Each  pound  of  this  steam  will  give  up  in  condensing  about  969  B.t.u. 
of  latent  heat  or  969  X  30  =  29070  B.t.u.  per  hour. 

Under  the  temperature  due  to  J^-lb.  gauge  pressure,  the  coil  would 
probably  give  off  300  B.t.u.  per  sq.  ft  of  surface.  Therefore  the  rating  of 
the  trap  under  the  conditions  of  this  example  would  be  29070  divided  by  300 
=  96.9  sq.  ft.  of  direct  radiation. 

In  Example  1,  the  rating  in  sq.  ft.  of  radiation  is  more  than  five  times 
that  in  Example  2,  the  difference  being  due  to  the  effect  of  differences  in 
pressure  on  the  same  trap,  which  in  both  cases  had  the  same  capacity. 

WEBSTER  MODULATION  SUPPLY  VALVES  :  Careful  consideration  should 
be  given  to  the  following  facts  concerning  ratings  of  this  type  of  apparatus : 

The  capacity  of  a  modulation  valve  should  be  based  on  the  quantity 
of  steam  expressed  in  pounds  per  hour,  or  the  equivalent  B.t.u.  of  latent 
heat  therein  at  1-lb.  pressure  above  atmospheric  pressure  which  will  flow 
through  the  valve  when  the  outlet  is  at  atmospheric  pressure. 

This  capacity  may  be  referred  to  as  the  number  of  square  feet  of  radiat- 
ing surface  which  will  absorb  the  total  latent  heat  of  the  steam  flowing 
into  the  surface  in  a  given  time,  at  the  commencement  of  which  the  tem- 
perature of  the  metal  of  the  radiation  and  the  room  are  at  a  stated  degree 
below  the  normal  room  temperature. 

The  steam  requirements  for  all  types  of  radiation  are  greatest  during 
the  heating-up  period.  This  is  the  period  during  which  the  cold  metal  is 
absorbing  heat,  while  at  the  same  time  the  radiator  as  a  whole  is  giving  off 
heat  by  radiation  and  convection  at  approximately  one  half  its  normal  rate. 
This  statement  is  approximate  because  the  temperature  of  the  radiating 
surface  is  gradually  increasing  from  the  cold  room  temperature  to  the  steam 
temperature,  during  this  period. 

Other  things  being  equal,  it  follows  that  the'longer  the  allowable  heating- 
up  period,  the  greater  is  the  proportion  of  capacity  which  may  be  expressed 
in  the  rating.  Each  type  of  radiation  having  a  different  weight  of  metal 
per  square  foot  of  heating  surface  and  a  different  heat  emission  rate,  will 
take  a  different  rating  of  inlet  valve  of  a  given  capacity. 

The  consensus  of  opinion  seems  to  be  that  the  rating  of  a  valve  should 
be  only  such  part  of  its  capacity  as  will  permit  the  heating  of  the  entire 
radiator  to  steam  temperature  from  a  room  temperature  of  40  deg.  fahr. 
in  20  minutes  from  the  time  the  valve  is  fully  opened,  and  this  is  taken 
as  the  heating-up  period  in  the  ratings  given  in  the  tables  in  this  chapter. 
Radiation,  according  to  type,  varies  in  weight  between  2.3  and  7  Ib.  per 
square  foot  of  surface. 

This  causes  a  marked  difference  in  the  steam  requirements  during  the 
heating-up  period,  as  well  as  a  marked  difference  in  the  rating  of  any  valve 
of  given  capacity. 

In  Table  23-1  the  warming-up  requirements  of  the  various  types  of 

234 


direct  radiation  in  general  use  and,  in  Table  23-2,  the  normal  heat  emission 
in  70-deg.  air,  have  been  averaged  under  five  classifications.  From  these 
averages,  the  factors  in  column  6  have  been  derived  by  which  the  capacity  of 
any  inlet  valve  in  pounds  of  steam  per  hour  at  1-lb.  differential  may  be 
converted  into  rating  in  square  feet  of  radiation  of  any  of  these  general 
classes. 

Table  23-1.    Basis  for  Rating  Inlet  Valves 

Heat  required  to  raise  temperature  of  metal  from  40  to  210  deg.  fahr.  in  20  minutes. 
Temperature  difference  170  deg.  fahr.     Specific  heat,  cast  iron  .12;  mild  steel  .117 

Avg.  wt.  per  sq.  ft.  cast-iron  floor  radiation  7.00  Ib.  x  .12    x  170  =142.80  B.t.u.  per  sq.  ft. 

"  cast-iron  wall  radiation  6.50   "   x  .12    x  170  =132.60      "  "     "     " 

"      "    "    "      sheet-steel  radiation     2.30   "  x  .117  x  170  =  45.75      "  "     "     " 

IJ^-in.  coil  radiation     5.20   "  x  .117  x  170  =103.42      "  "     "     " 
1     -in.  coil  radiation      4.85    "  x. 117x170=   96.17 

Table  23-2.     Rating  Values  for  Modulation  Valves 
For  various  types  of  direct  heating  surface 


Col.  1 

Col.  2 

Col.  3 

Col.  4 

Col.  5 

Col.  6 

B.  t.  u.  per  sq. 
ft.  per  hr.  to 
maintain  210° 
in  the  rad.  with 
room  temp,  of 
70° 

B.  t.  u.  emitted 
in  1-3  hour 
during  warming- 
up  period  =  1-6 
hourly  rate 

B.  t.  u.  per  sq. 
ft.  to  raise 
temperature 
of  metal 

B.  t.  u.  per  sq. 
ft.  req'd  in  20 
minute  period. 
Total  of 
Cols  2  and  3 

Combined 
hourly  rate 
in  B.  t.  u. 

Co,.4xf? 

Factor  for  con- 
verting capacity 
into  rating 
970  +  Col.  5 

Cast-iron  floor  radiation            245 
Cast-iron  wall  radiation             296 
Sheet-steel  radiation                   260 
1  J^-in.  pipe  coil  radiation         326 
1-in.  pipe  coil  radiation              296 

40.8 
49.33 
43.33 
54.33 
49.33 

142.8 
132.6 
45.75 
103.42 
96.47 

183.6 
181.93 
89.08 
157.75 
145.80 

551 
546 
267 
473 
437 

1.76\AvK. 
1.78/1.77 
3.63 
2.05 

2.22 

To  ascertain  the  rating  in  terms  of  square  feet  of  radiation  of  any  inlet 
valve  for  20-min.  heating-up  period,  multiply  the  capacity  of  the  valve  ex- 
pressed in  pounds  of  steam  per  hour  at  that  given  pressure  difference  by  the 
factor  in  column  6  corresponding  to  type  of  radiation  and  the  result  will  be 
the  square  feet  of  that  surface  heated  from  40  deg.  to  210  deg.  in  20  minutes. 

To  ascertain  ratings  for  any  other  period  than  20  minutes,  a  new  table 
must  be  prepared  retaining  columns  1  and  3.  New  column  2  will  be  deter- 
mined by  multiplying  the  B.t.u.  in  column  1  by  one-half  the  selected 
warming-up  period  in  parts  of  one  hour.  (See  seventh  paragraph,  page  234) . 

New  column  4  will  be  the  sum  of  new  column  2  and  standard  column  3. 

New  column  5  will  be  the  product  of  new  column  4  by  (60  divided  by 
the  selected  warming-up  period  in  minutes). 

New  column  6  will  be  the  quotient  of  new  column  5  into  the  latent 
heat  in  1  Ib.  of  steam  at  pressure. 

Having  the  rating  for  any  particular  valve  for  a  particular  class  of 
radiation  at  1-lb.  differential,  ratings  at  other  pressure  differences  may  be 
closely  approximated  by  multiplying  the  1-lb.  rating  by  the  square  root  of 
the  other  pressure  difference. 

The  normal  average  flow  to  a  heated  cast-iron  radiator  is  about  250 
B.t.u.  A  properly  designed  modulation  valve,  when  0.6  open  should  supply 
the  radiator  with  y'j  of  the  full-open  flow,  which  is  the  approximate  need 

235 


for  full  modulation  effect.  The  balance,  or  ^  of  the  opening,  is  thus  available 
for  a  quick  warming-up  period  (20  minutes)  when  the  valve  is  full  open. 

Owing  to  the  wide  difference  in  area  between  standard  pipe  sizes,  a 
valve  of  say  1-in.  size  must  be  used  on  all  different  sizes  of  radiators  between 
its  own  maximum  rating  and  that  of  the  next  smaller,  or  %-in.  valve.  The 
wide-open  1-in.  valve  will  therefore  produce  a  much  more  rapid  heating-up 
effect  when  connected  to  a  radiator  which  is  a  little  too  large  for  a  %-in. 
valve,  and  the  full  modulation  effect  will  be  reached  much  before  the  valve 
is  0.6  open,  which  is  the  normal  position  for  full  modulation  effect.  This 
problem  might  be  solved  were  it  not  for  commercial  considerations,  by 
putting  a  restrictive  valve  piece  in  those  valve  bodies  which  are  used  on 
the  lower  half  of  the  range.  This  would  limit  the  flow  at  0.6  open  to 
about  half  way  between  the  maximum  for  that  particular  valve  and  the 
maximum  of  the  next  smaller  size.  In  this  way,  a  valve  having  a  total 
range  of  45  to  78  sq.  ft.  of  radiation  at  0.6  open  can  be  limited  to  45  to  60 
sq.  ft.  of  radiation,  thus  gaining  the  whole  0.6  range  for  controlling  the 
degree  of  modulating  effect,  instead  of  commencing  to  modulate  only 
after  about  %  closed  and  having  but  the  remaining  H  of  the  total  move- 
ment for  graduating  the  modulating  effect. 

The  ratings  of  each  Webster  Type  W  Modulation  Valve  for  the  stated 
conditions,  at  various  positions  of  the  pointer,  are  indicated  in  Figure  23-1, 
which  in  conjunction  with  Table  23-3  will  assist  in  selection  of  a  valve  of 
the  proper  size  for  any  set  of  conditions. 

Initial  steam  pressure  alone  is  not  a  correct  basis  for  valve  rating  or 
sizing.  It  is  far  safer  to  allow  for  maximum  possible  drop  in  line  pressure 
when  figuring  the  inlet  pressure  at  the  valve.  Similarly,  allowance  must  be 
made  for  variation  in  return  line  pressure,  especially  with  vacuum  systems. 


OPEN 
10 


ifl 


24 


12-- 


SHUT 


7 


40  80  120  160  200  240  280 

Square  Feet  of  Average  Cast-iron  Radiation 


320 


360 


400 


Fig.  23-1.     Rating  of  Webster  Type  W  Modulation  Valves.     Based  upon  a  differential  of  one  pound  at 
the  valve  and  fully  heating  the  radiator  in  20  minutes  in  a  room  temperature  of  10  deg.  fahr. 


236 


The  condensation  rate  of  radiation  varies  with  the  type  of  radiation  or 
coil,  its  location,  and  the  difference  between  outside  and  room  temperatures, 
and  allowance  must  be  made  accordingly. 

Table  23-3.    Ratings  of  Webster  Type  W  Modulation  Supply  Valves 

In  square  feet  of  average  cast-iron  direct  radiation  at  various  pressure  differences.  Based  on  20-min. 
heating-up  period  from  40  deg.  fahr.  initial  temperature* 


Pressure  difference 

Size  of  valves 

1  01. 

2  oz.                       4  oz. 

6  oz.                   8  oz. 

1  lb. 

Square  feet  of  average  cast-iron  direct  radiation 

IF 

19 
40 

27 
57 

38 

80 

47 
98 

54 
113 

76 
160 

i" 

65 

94 

132 

i  63 

187 

265 

W 

112 

160 

225 

276 

319 

450 

Table  23-4.    Ratings  of  Ordinary  Angle-pattern  Radiator  Supply  Valves 

In  square  feet  of  average  cast-iron  direct  radiation  at  various  pressure  differences.    Based  on  20-min. 
heating-up  period  from  40  deg.  fahr. initial  temperature* 


Size  of  valve 


Pressure  difference 


lac. 

2  oz.                    4  oz.                    6  oz. 

Soz. 

1  tb. 

Square  feet  of  average  cast-iron  direct  radiation 

\/l* 

21 

30 

42 

52 

60 

84 

W 

44 

62 

87 

107 

124 

175 

1" 

77 

102 

147 

180 

204 

294 

IX" 

126 

180 

252 

308 

360 

504 

\w 

187 

258 

364 

446 

516 

728 

Table  23-5.     Ratings  of  Webster  Double-service  Valves 

In  square  feet  of  average  cast-iron  direct  radiation  at  various  pressure  differences.    Based  on  20-min. 
heating-up  period  from  40  deg.  fahr.  initial  temperature  * 


Size  of  valve 


Pressure  difference 


i;; 

1  oz. 

2oz. 

4oz. 

6  oz. 

8  oz. 

lib. 

Square  feet  of  average  cast-iron  direct  radiation 

42 
69 
119 
172 

60 

97 
168 
243 

85 

138 
238 
343 

104 
168 
292 
420 

120 
195 
336 
486 

166 

275 
475 
685 

*  If  the  quick  heading-up  feature  is  disregarded  and  ratings  are  desired  for  normal  requirements  only, 
after  the  radiator  has  been  heated  up,  multiply  the  values  in  the  tables  by  2.2. 

WEBSTER  RETURN  TRAPS:  Both  the  Webster  Sylphon  Return  Trap 
and  the  Webster  No.  7  Return  Trap  are  rated  on  the  basis  of  the  quantity 
of  condensation  which  they  will  pass  under  stated  conditions. 

Owing  to  the  fact  that  these  traps  when  cold  are  fully  open,  the  warm- 
ing-up period  of  a  radiator  has  no  bearing  upon  the  problem  of  rating  return 
traps  even  though  the  discharge  of  air  and  water  are  then  at  maximum. 

The  thermostatically  actuated  members  of  Webster  Sylphon  and  No. 
7  Return  Traps  are  sensitive  to  very  slight  changes  of  the  temperature  of 

237 


the  surrounding  medium.  The  motion  of  the  members  is  due  to  the  difference 
in  pressure  and  temperature  on  a  hermetically  sealed  charge,  partially 
liquid,  partially  gas  and  vapor,  which  responds  to  changes  in  temperature 
with  material  changes  in  volume  and  pressure,  and  this  provides  a  power- 
ful force  to  actuate  the  valve  piece. 

Table  23-6.     Ratings  of  Webster  Return  Traps  in  Pounds  of  Condensation  and 
B.t.u.    per  Hour  at  Various  Pressure  Differences 


Size  and  type 
of  trap 

Pressure  difference 

2  01. 

4  os. 

6  oz. 

8oz. 

1  lb. 

Lb.    B.  t.  u. 

Lb.    B.  t.  u. 

Lb.    B.  t.  u. 

Lb.    B.  t.  u. 

Lb.    B.  t.  u. 

^"-512  &  712 

Ji"-522  &  722 
M"-533  &  733 
l"-544  &  741 
lM"-545  &  745 

14    13580 
22    21340 
66    64020 
133   129010 
265   257050 

19    18430 
31    30070 
94    91180 
188   182360 
375   363750 

23    22310 
38    36860 
115   111550 
230   223100 
459   445230 

27    26190 
44    42680 
132   128040 
265   257050 
530   514100 

38    36860 
62    60140 
187   182390 
375   363750 
750   727500 

Table  23-7.     Initial  Steam  Pressures  and  Pressure  Drops  through  Supply  Pipes, 

Modulation  Valves  and  Return  Traps  of  the  Heating  Systems  of 

Different  Types  of  Buildings 


Case 

Approximate  steam 
pressure  in 
zero  weather 

Pressure  drop 
through  supply 
piping 

Average  pressure  differential 
through  valves 

Modulation 
supply  valve 

Return  trap 

A 

Vl  to  %  lb. 

}/%  lb.  with  mini- 
mum run-400  ft. 

2  oz. 

2oz. 

B 

1  to  \]/i  lb. 

}^  lb.  with  mini- 
mum run-400  fj,. 

4oz. 

4  to  6  oz. 

C 

1  to  2  lb. 

%  lb.  with  mini- 
mum run-400  ft. 

4  oz. 

4  to  6  oz. 

D 

\Y2  to21b. 

%  to  1  lb. 

4  oz. 

4  to  6  oz. 

E 

\Yi  to21b. 

lib. 

4  to  6  oz. 

8  to  12  oz. 

NOTE:  In  modulation  systems  in  conjunction  with  low-pressure  boilers  of  limited  water  capacity,  it  is  essential  that  the 
drop  in  pressure  through  the  system  be  kept  well  below  the  pressure  due  to  the  static  head  between  the  modulation  vent  trap 
and  the  water  line  of  the  boiler.  Special  apparatus  may  be  provided  to  return  water  to  boiler  where,  owing  to  structural  con- 
ditions, the  above  outlined  conditions  cannot  be  obtained 

Note:  Webster  Water-seal  Traps  in  the  few  cases  where  they  are  used 
are  rated  same  as  the  Sylphon  and  No.  7  Traps. 

SELECTION  OF  MODULATION  SUPPLY  VALVES  AND  RETURN  TRAPS: 
For  any  given  installation  the  choice  of  the  proper  sizes  of  modulation 
valves  and  return  traps  will  depend  upon  the  available  pressure  differential 
through  the  valves. 

This,  in  turn,  is  dependent  upon  the  steam  pressure  maintained  at 
the  boiler  and  the  drop  in  pressure  through  the  piping  system.  While  it 
is  not  possible  to  lay  down  hard  and  fast  rules  which  are  applicable  for  every 
installation,  the  following  cases  are  given  as  representative  types  of  systems 
in  general  use.  Cases  A  to  D  inclusive,  given  in  table  23-7,  relate  to 

238 


modulation  systems,  with  open  returns  terminating  at  the  boiler  in  a 
modulation  vent  trap  or  some  similar  forms  of  apparatus.  Case  E  is  the 
usual  type  of  vacuum  system.  The  proper  sizing  of  supply  and  return  pipes  is 
explained  in  detail  in  Chapter  1 1  and  the  pressure  drops  referred  to  below  are 
found  in  Table  11-8. 

Case  A :  Residences  and  small  apartments  where  the  firing  is  inter- 
mittent, frequently  extending  over  eight  or  perhaps  ten-hour  periods  and 
where  it  is  necessary  to  operate  at  low  steam  pressure.  In  mild  weather  it 
may  be  possible  to  circulate  steam  through  the  entire  system  at  or  perhaps 
slightly  below  atmospheric  pressure.  In  zero  weather  a  pressure  will  be 
maintained  at  the  boiler  of  from  %  lb.  to  %  lb.  depending  upon  the  kind 
of  fuel,  length  of  firing  period  and  condition  of  fire. 

Case  B:  Very  large  residences,  apartment  houses,  small  offices  and 
public  buildings  where  large  size  cast-iron  sectional  or  steel  boilers  are 
installed,  operating  at  low  steam  pressure  and  under  the  care  of  a  regular 
attendant,  with  continuous  firing  instead  of  intermittent. 

Case  C:  Schools  and  similar  buildings  containing  large  amounts  of 
indirect  radiation  where  there  are  periods  of  interruption  in  maintaining 
pressure  on  the  system  and  where  quick  circulation  is  desired  when  starting. 

Case  D:  Buildings  where  the  pressure  is  maintained  constant  by  means 
of  a  reducing  valve  and  steam  is  taken  at  higher  pressure  either  from  its 
own  boiler  plant  or  from  a  street  system. 

Case  E:  Office  buildings,  industrial  plants,  etc.  in  which  a  vacuum 
system  is  installed  using  live  steam  at  reduced  pressure,  or  exhaust  steam 
from  engines,  pumps  and  auxiliary  apparatus,  supplemented  by  live  steam 
passed  through  a  reducing  valve.  The  steam  pressure  at  the  entrance  to 
the  supply  piping  in  zero  weather  will  range  from  !}/£  to  2  lb.  and  the  vacuum 
on  the  far  end  of  the  return  line  will  be  approximately  2-in. 

WEBSTER  HEAVY-DUTY  RETURN  TRAPS:  This  trap  is  for  use  where 
large  quantities  of  condensation  are  to  be  handled  at  any  temperature. 
It  has  a  cone-shaped  float-operated  valve  piece  seating  on  a  sharp-edged 
orifice,  the  seat  being  below  the  low-water  line  of  the  trap.  The  air  entering 
the  trap  is  allowed  to  pass  to  the  return  line,  through  a  connection  controlled 
by  a  thermostatically  operated  trap  discharging  through  a  cored  passage  to 
the  return  line.  In  special  cases  the  opening  through  the  air  orifice  may  be 
adjusted  by  hand. 

Table  23-8.    Ratings  of  Webster  Heavy-duty  Traps  in  Pounds  per  Hour  at 
Various  Pressure  Differences  Through  the  Valve 

No  allowance  made  for  pressure  drop  in  the  connecting  piping  between 
radiation  and  trap  or  from  trap  through  run-out  to  return 


Size 
of  trap 

Pressure  difference 

HLb. 

1  Lb. 

2  Lb. 

3Lb. 

4Lb. 

S  1.1,. 

10  Lb. 

15  Lb. 

0019 
019 
119 
219 

TIKI 
1250 
2100 
5600 

10(10 
1800 
3000 
8000 

1400 
2500 
1200 
11200 

1700 
3050 
5100 
13600 

2000 
3600 
6000 
16000 

2200 
4000 
6700 
17900 

3150 
5700 
9500 
25300 

3900 
7000 
11700 
31100 

WEBSTER  SERIES  20  MODULATION  VENT  TRAPS:   Capacities  of  Series 
20  Modulation  Vent  Traps  are  based  upon  the  assumption  of  an  air  flow  of 

239 


6000  cu.  ft.  per  hour  through  a  vent  orifice  of  1  sq.  in.  area  from  a  pressure 
of  1  Ib.  above  atmosphere  to  atmospheric  pressure.  This  quantity  is 
obtained  as  follows: 

Velocity  of  flow  in  feet  per  second  is  V  =  C  y  2  gh,  and  the  quantity 
in  cubic  feet  per  hour  is  Q  =  3600  x  av.  in  which  Q  is  the  quantity  in  cubic 
feet,  c  is  a  constant  (0.7),  h  is  the  height  of  a  column  of  air  in  feet,  required 
to  produce  a  pressure  of  1  Ib.  per  sq.  in.,  a  is  the  area  of  the  orifice  in 
square  feet,  v  is  the  velocity  in  feet  per  second  and  g  is  32.17. 

1  Lb.  of  air  contains  approximately  13.2  cu.  ft.  For  any  other  pressure 
difference  not  varying  greatly  in  amount  from  the  above  standard  pressure 
difference,  the  quantity  of  discharge  will  be  substantially  proportional  to 
the  square  roots  of  the  pressure  difference.  Assuming  that  50  sq.  ft.  of 
cast-iron  radiation,  with  connecting  supply  pipes,  will  contain  1  cu.  ft.  of 
space,  from  which  the  air  must  be  discharged  before  steam  will  enter,  the 
following  basic  data  applies  for  Modulation  Vent  Traps. 

Table  23-9.    Basic  Data  for  Modulation  Vent  Traps 


Size  of  trap 

0020 

020 

120 

220 

320 

Cubic  feet  of  air  discharged  per 
hour  at  1  Ib.  differential 

85 

660 

1176 

2652 

4710 

Cubic  feet  of  air  discharged  per 
hour  at  1  oz.  differential 

21 

165 

294 

663 

1178 

Square  feet  of  direct  radiation 
per  hour  at  1  oz.  differential 

1050 

8250 

14700 

33150 

58900 

Referring  to  page  117,  it  is  to  be  noted  that  air  vent  traps  are  rated 
on  the  basis  of  flow  of  initial  air  from  a  system  in  40  min.  with  1-oz. 
differential  pressure  through  the  system.  The  table  below  gives  the  ratings 
on  this  basis  for  which  the  Webster  Modulation  Vent  Traps  should  be 
applied. 

Table  23-10.     Ratings  of  Series  20  Modulation  Vent  Traps 


Size  of  trap 

0020 

020 

120 

220 

320 

Square  feet  of  direct  radiation 
in  40  min.  at  1  oz.  pressure 

700 

5500 

9800 

22100 

39265 

No.  of  i-in.  unit  vent 
valves  required 

1 

1 

2 

s 

5 

MODULATION  VENT  VALVES  are  required  wherever  it  is  desired  at  times 
to  operate  the  heating  system  at  a  pressure  less  than  atmospheric.  Where 
large  heating  units  are  under  automatic  temperature  control,  the  use  of 
these  vent  valves  is  inadvisable  unless  vacuum  breakers  are  provided  at  the 
proper  points  in  the  piping  system. 


240 


CHAPTER  XXIV 

Appliances  for  Webster  Systems  of 
Steam  Heating 

WEBSTER  Appliances   used   as  parts  of  heating  systems  are  illus- 
strated  and  briefly  described  in  the  following  pages. 
These  appliances  include: 

Return  Traps  Gauges 

Heavy-duty  Traps  Modulation  Vent  Traps 

High-differential  Heavy-duty  Traps  Modulation  Vent  Valves 

Modulation  Supply  Valves  Damper  Regulators 

Double-service  Valves  Hylo  Vacuum  Controllers 

Oil  Separators  Hylo  Traps 

Grease  and  Oil  Traps  Conserving  Valves 

Suction  Strainers  Boiler  Feeders 

Dirt  Strainers  High-pressure  Traps 

Vacuum-pump  Governors  Hydro-pneumatic  Tanks 

Lift  Fittings  Expansion  Joints 

Return  Tanks  Steam  Separators 

Water  Accumulators  Feed-water  Heaters 
Vapor  Economizers 

Return  Traps  for  Automatically  Removing  Water  of 
Condensation  and  Air  from  Heating  Units 

The  return  trap,  to  be  perfect  in  operation,  should — 

(a)  Allow  the  condensation  to  escape  at  a  temperature  slightly  below 
that  of  the  steam. 

(6)  Drain  the  radiator  thoroughly  by  gravity,  without  the  assistance 
of  pressure  or  vacuum.  A  water-logged  radiator  loses  efficiency  because 
part  of  the  heating  is  being  done  by  the  water  condensed  from  steam,  which 
is  at  lower  temperature,  and  because  a  water-logged  radiator  is  also  an  air- 
bound  radiator. 

(c)  Permit  continuous  removal  of  ah*.  An  air-bound  radiator  loses 
efficiency  because  the  steam  cannot  completely  fill  it. 

(rf)  Automatically  close  to  prevent  loss  or  waste  of  steam. 

(e)  Work  within  the  widest  necessary  range  of  pressure  and  vacuum 
variation. 

(/)  Require  no  adjustment  under  such  variations. 

(g)  Be  noiseless  in  operation,  if  used  where  noise  is  objectionable. 

(h)  Be  so  designed  that  the  valve  will  close  even  where  dirt  may  be 
present  in  normal  quantities. 

(i)  Be  durable  and  require  little  or  no  attention  or  repairs. 

241 


The  efficiency  of  the  radiator  will  depend  upon  how  nearly  the  return 
trap  meets  these  requirements. 

A  return  trap  working  sluggishly  will  not  only  hold  back  the  water, 
but  will  "bottle  up"  the  air  and  air-bind  the  radiator,  thus  defeating  the 
very  purpose  of  a  vacuum  system. 

As  different  methods  must  at  times  be  employed  in  connection  with 
direct  radiators,  blast  sections,  riser  drips,  main  drips,  dripping  hot-water 
generators,  factory  coils,  etc.,  Webster  Return  Traps  are  made  in  several 
forms,  at  least  one  of  which  will  meet  the  requirements  of  any  installation. 


100%  RADIATOR  EFFICIENCY 


SUCCESSFUL 
OPERATION 
AT  VARYING 
PRESSURES 


AUTOMATIC  REMOVAL 
OF  AIR  AND  WATER 
OF  CONDENSATION 
WITH  NO  LEAK- 
OF STEAM 


99.5  PLUS  PER  CENT 

NO  INTERFERENCE  BY  DIRT  WITH  THE  PROPER  FUNC-          VAPOR  EFFICIENCY 
TIONING  OF  TRAP 

Fig.  24-1.     The  requirements  of  a  perfect  radiator  trap 

The  type  and  capacity  of  the  trap  required  depend  upon  the  point  of 
application,  the  amount  of  air  and  water  to  be  removed,  the  character  of 
the  heating  surface  and  the  pressure  and  vacuum  carried.  It  is  important 
that  all  of  these  conditions  shall  be  studied  carefully  before  selection  is  made 
of  the  size  and  type  of  trap  for  specific  applications. 

The  Webster  Sylphon  Trap 

The  Webster  Sylphon  Trap  has  been  specially  designed  to  meet  the 
requirements  for  a  perfect  radiator  trap.  It  maintains  the  highest  possible 
efficiency  within  the  heating  surface  by  the  removal  of  all  of  the  products  of 
condensation,  and  as  this  is  effected  without  loss  of  steam,  it  is  economical 
in  the  highest  degree.  The  economy  is  especially  apparent  when  reduced- 
pressure  live  steam  is  used  in  whole  or  in  part,  or  where,  before  its  appli- 
cation it  has  been  necessary  to  waste  large  quantities  of  cold  water  to  cool 
the  heating  system  returns  before  they  enter  the  vacuum  pump. 

The  operating  member  consists  of  a  Sylphon  bellows,  which  carries  a 

242 


conical-shaped  valve  piece,  closing  against  a  sharp-edged  seat.  The  bellows 
member  is  very  sensitive,  operating  to  close  or  open  the  valve  port  by  the 
slightest  change  in  the  temperature  of  the  surrounding  medium,  and  is  the 
most  durable  form  of  thermostatic  device  so  far  known.  The  multiple 
construction  of  the  seamless  brass  folds  forming  the  bellows  distributes  the 


Fig.  21-2.     No.  512  Model  H  Webster  Sylphon  Trap.    Size  of  pipe  connections,  J4-in. 


Fig.  21-3.    No.  522  Model  H  Webster  Sylphon  Trap.     Size  of  pipe  connections,  J^-in.     Nos.  512  and  522 

differ  in  rating  and  lift  of  valve,  No.  522  being  larger 

No.  523  has  same  size  body  mechanism  and  rating  as  No.  522,  but  has  :;  ,-in.  pipe  connections  to  meet 

unusual  specifications  in  that  respect 

strain  of  movement  and  increases  the  life  of  the  operating  member.  In- 
crease in  steam  pressure  on  the  outside  of  the  bellows  is  compensated  by  the 
increase  in  pressure  on  the  inside  of  the  bellows. 

The  sensitiveness  of  this  member  is  due  to  the  flexibility  of  the  walls 

243 


of  the  bellows  to  movement  in  the  desired  direction  and  the  small  amount 
of  movement  of  each  fold  when  acted  upon  by  the  pressure  surrounding  and 
also  that  generated  within  the  bellows.  The  sum  of  the  small  movement 
of  each  of  the  many  folds  gives  a  greater  total  lift  of  the  valve  than  any  other 
device  for  similar  purpose. 

The  conical  valve  piece  and  sharp-edged  seat  give  increased  capacity 


Fig.  21-4.     No.  533  Model  H  Webster  Sylphon  Trap.     Size  of  pipe  connections,  %-in. 

No.  534  has  same  size  body  with  1-in.  pipe  connections  to  meet  unusual  specifications 
No.  544  is  similar,  but  larger  throughout  for  1-in.  pipe  connections  and  greater  duty 
No.  545  is  the  largest  in  proportions  and  ratings.     For  IJ^-in.  pipe  connections 

for  discharge  of  water,  and  the  valve  does  not  become  inoperative  due  to 
presence  of  dirt  and  scale. 

The  Webster  Sylphon  Trap  will  close  quickly  and  positively  when  steam 
reaches  the  bellows,  while  the  water  and  air  will  be  freely  withdrawn  or  dis- 
charged at  temperature  slightly  below  that  of  steam  at  existing  pressure. 

This  means  that  every  radiator  in  use  will  be  thoroughly  efficient  in 
heating,  as  there  will  be  no  "pocketing"  of  air  or  "bottling  up"  of  water 
within  the  radiator. 

As  the  valve  is  full  open  when  cold,  the  radiator  will  be  fully  drained 
when  steam  is  turned  off,  and  the  vacuum  condition  existing  in  the  return 
line  will  extend  within  the  radiator,  assisting  circulation  when  steam  is 
again  turned  on. 

OPERATION  :  As  the  steam  first  flows  into  the  cool  radiator,  it  expels  the 
contained  air  and  initial  condensation  through  the  wide-open  trap.  As  the 
radiator  warms  up  from  inflow  of  steam,  the  bellows  commences  to  expand, 
but  remains  partially  open  as  long  as  the  air  and  water  in  the  trap  are  at  a 
lower  temperature  than  that  of  the  steam.  The  moment  the  air  is  entirely 
expelled  from  trap  body,  and  replaced  with  steam,  the  valve  closes.  It 
opens  again  when  water  and  air  at  a  temperature  slightly  less  than  that  of 
the  steam  accumulate  in  the  trap.  Then,  as  the  water  and  air  escape  and 
are  replaced  in  the  trap  body  by  steam,  the  trap  again  closes,  thus  complet- 
ing its  cycle. 

244 


Table  24-1.    Models  and  Dimensions  of  No.  5  Sylphon  Traps  for  Working 
Pressure  Up  to  10  Lb.  per  Sq.  In. 

For  convenience  in  making  pipe  connections,  Webster  Series  5  Sylpbon  Traps  of  the  smaller  sizes  are  made 
with  four  types  of  bodies  as  shown.     Model  H  or  angle  is  the  one  roost  used 


Model  H 
Angle 


Model  G 
Straightway  offset 


Model  R 
Right  corner 


Model  L 
Left  corner 


Fig.  2 1-5.     Bodies  of  Webster  Series  5  Sylphon  Traps 


Size 

Trap  no. 
&  model 

A 

B 

c 

D 

W 

512H 

3" 

W 

W 

W 

w 

522H 

3^" 

1H" 

ift" 

5H" 

K" 

523H 

3H" 

2" 

1ft" 

5X" 

K" 

533H 

4ft" 

2*/s" 

IK" 

5^" 

I" 

534H 

W 

2%" 

IK" 

5H" 

I" 

544H 

4ft" 

2ft" 

2" 

6H" 

\Y4" 

545H 

4K" 

2ft" 

2" 

6H" 

Fig.  24-8 


Fig.  24-7 


Size 

Trap  no.  and  model 

A 

B 

C 

D 

E 

H" 

512O,  512R  or  5121. 

3" 

!«' 

1" 

4M" 

\w 

X" 

522G.  522R  or  522L 

3H" 

1H' 

\yt" 

5H" 

1H" 

H" 

523G,  523R  or  5231, 

3H" 

W 

W 

8ft" 

i«" 

K" 

533G 

4A" 

2A' 

IK" 

5H" 

Not 

1" 

534G 

4K" 

2A' 

i«" 

6" 

made 

For  ratings,  see  Table  23-6,  page  238. 
245 


The  Webster  No.  7 


Fig.  24-9     Exterior  and  interior  of  No.  722  Webster  Trap 

Webster  No.  7  Traps  also  realize  all  of  the  requirements  for  thoroughly 
satisfactory  operation  as  radiator  traps.  They  are  applied  at  the  outlets 
of  steam  radiators  and  coils,  at  drip  points 
on  steam  supply  lines  and  risers  and  at  the 
outlets  of  blast  sections  on  fan  coils  and 
provide  continuous  free  and  thorough  re- 
moval of  entrained  air  and  water  of  con- 
densation, without  permitting  any  live  steam 
to  escape  to  waste  in  the  return  lines. 

The  inlet  of  the  trap  is  attached  to  the 
radiator,  coil  or  supply  line  by  means  of  the 
union  connection,  and  the  outlet  is  piped 
into  the  return  line. 

The  thermostatic  member  is  inboard  of 
the  valve  seat  where  not  affected  by  pressure 
or  temperature  in  the  return  line. 

The  diaphragm,  which  forms  the  active 
part  of  the  operating  member,  is  built  of 

Table  24-2.     Models  and  Dimensions  of  Webster 

Series  7  Traps  for  Working  Pressure 

Up  to  10  Lb.  per  Sq.  In. 

For  convenience  in  making  pipe  connections,  Webster  Series 
7  Traps  are  made  with  four  types  of  bodies  as  shown.  Model 
H  or  angle  is  the  one  most  used 


Size 

Trap 
no. 

A 

B 

c 

D 

E 

J  /// 

712H 

3^" 

1A" 

l»" 

2W" 

V%' 

722H 

3^" 

1ft" 

ill" 

3ft" 

g" 

723H 

3jr 

1ft" 

1H" 

3A" 

g" 

733H 

w 

IH" 

2X" 

4A" 

1" 

744H 

w 

2" 

2y2" 

4A" 

\%" 

745H 

*H" 

2" 

2>A" 

4A" 

712GI 

w 

712R 

3M" 

2}4" 

X" 

Sft" 

2W" 

712LI 

722G 

w 

722IU 

3M" 

21A" 

H" 

•W 

2J4" 

722LJ 

For  ratings  see  Table  23-6,  page  238 


Fig.  24-11 


24fi 


four  successive  phosphor-bronze  plates  instead  of  the  usual  two  and  for  that 
reason  there  is  greater  diaphragm  movement  and  the  valve  has  greater  lift 
than  usually  found  in  traps  of  similar  types. 

The  expansion  and  contraction  of  the  diaphragm  member  is  produced 
by  differences  in  volume  and  pressure  of  a  hermetically-sealed  fluid  charge 
in  response  to  changes  in  temperature.  Even  a  very  slight  temperature 
change  produces  a  powerful  force  to  actuate  the  conical  valve  piece,  which 
in  closing,  fits  tightly  on  a  sharp-edged  seat. 

No  part  of  the  valve  mechanism  is  impaired  by  the  quantities  of  the 
scale  and  dirt  which  normally  exist  in  steam-heating  systems. 

Webster  Heavy-duty  Traps 


Fig.  24-12.    Series  19T  Webster  Heavy-duty  Trap 
with  thermostatically  controlled  air  bypass 

SERIES   19T  WITH  THERMOSTATI- 
CALLY CONTROLLED  AlR  BYPASS.      FOR 

15-LB.  MAXIMUM  OPERATING  PRESSURE  : 
The  Webster  Heavy-duty  Trap  handles 
unusually  large  quantities  of  conden- 
sation, and  is  for  dripping  main  supply 
risers  or  mains  entering  or  leaving  the 
building,  for  draining  large  sections 
of  blower  coils  or  pipe  manifolds,  for  draining  hot-water  generators,  etc. 

Insofar  as  the  discharge  of  condensation  is  concerned,  this  trap  operates 
on  the  float  principle  and  has  a  large  water  outlet  to  withdraw  the  con- 
densation as  quickly  as  possible  from  the  unit  to  be  drained. 

Air  is  eliminated  by  means  of  a  thermostatically  actuated  by-pass,  as 
shown  in  Figure  24-12.  The  operating  device,  the  valve  piece  and  seat  are 
the  same  as  used  in  the  Webster  No.  7  Trap. 

247 


The  body  and  cover  are  of  cast  iron.  The  cover  is  bolted  on,  easily 
removable  and  so  designed  that  all  interior  parts  are  exposed  for  inspection 
upon  its  removal.  The  outlet  is  in  the  bottom  of  the  body,  and  the  inlet 
may  be  on  either  end,  with  the  opposite  opening  plugged.  It  is  recom- 
mended that  wherever  practical  the  inlet  farthest  away  from  the  valve  be 
used.  An  opening  is  provided  at  the  bottom  of  the  float  chamber  as  a  clean- 
out  by-pass  and  for  draining  the  trap  when  out  of  use. 

The  float  has  ample  leverage  to  avoid  sticking  of  the  valve.  The  cone- 
pointed  valve  and  square-edged  seat  prevent  accumulation  of  dirt  where  it 
might  clog  the  port.  The  valve  is  water-sealed  at  all  times,  as  the  water 
level  is  always  well  above  the  seat.  The  float  lever  is  kept  within  the  ver- 
tical plane  of  action  by  guide  flanges  cast  into  the  trap  body. 

This  trap  can  also  be  furnished  special  with  hand-controlled  air  and 
by -pass,  where  unusual  conditions  require  such  construction.  In  such  cases 
the  air  port  is  adjustable  for  any  desired  degree  of  constant  leakage. 

Some  of  the  many  practical  applications  of  the  Series  19T  Trap  will  be 
found  in  Chapter  22.  Ratings  are  given  on  page  239  and  dimensions  on 
page  249. 


Fig.  24-13.  Conventional  arrangement  of  Series 
20  Webster  High-differential  Heavy-duty  Trap 
and  Special  Webster  Dirt  Strainer  (Inlet  pipe 
may  be  connected  to  opposite  end  if  desired) 


Fig.  24-14.  Series  20  Webster  High-differential 
Heavy-duty  Trap  for  working  pressures  up  to 
.iO  Ib.  per  sq.  in. 


248 


HiGH-DlFFERENTIAL  TYPE,  SERIES   20,      FOR  WORKING    PRESSURES  UP 

TO  50  LB.  PER  SQ.  IN.:  The  Webster  High-differential  Heavy-duty  Trap 
is  recommended  for  steam  pressures  higher  than  15  Ib.  and  where 
large  quantities  of  condensation  may  be  discharged.  It  is  particularly 
applicable  to  problems  like  or  similar  to  those  described  in  Chapter  19. 

The  trap  body  is  constructed  of  cast  iron  and  has  an  easily  removable 
cover  of  the  same  material.  The  valve  is  of  the  balanced  type  and  operates 
against  a  steam-brass  seat.  The  ball  float  is  extra  heavy  to  withstand  the 
higher  pressures. 

The  Webster  High-differential  Heavy-duty  Trap  may  be  operated 
with  a  constant  leakage  through  a  hand-adjusted  air  vent,  though  the  best 
practice  calls  for  control  of  the  air  discharge  by  means  of  a  thermostatically 
actuated  valve  in  a  by-pass  of  pipe  and  fittings  as  shown  in  Figure  24-16. 
It  is  important  to  note  in  this  case  of  higher  than  ordinary  steam  pressure, 
that  the  thermostatic  trap  must  be  of  the  No.  8  Sylphon  type.  (See  page  275.) 

Table  24-3.     Dimensions  of  Webster  Heavy-duty  Traps 

All  dimensions  in  inches  and  subject  to  slight  variation 


Drain  Opening 
Fig.  2 1-15.     Standard  type— Series  19T 


A-SIze  Outlet 


\  Plugged 
Dclin  Opening 


Fig.  24-16.      High-differential  type— Series  20 


For  ratings  of  Heavy-duty  Traps  see  Table  23-8,  page  239 
Series  19T,  with  thermostatically  controlled  by-pass 


Number 


0019-T 
019-T 
119-T 
219-T 


A< 


20% 


1 

1 

IK 

IK 


12K 
15 


19H 


9% 


Series  20,  high-differential  type 


Number 

020 
120 

220 


A" 


I 


20^ 


1 

IK 
IK 


15 


249 


The  Webster  Type  W  Modulation  Valve 


Fig.  24-17.     The  Webster  Type  W  Modulation  Valve — shown  in  partly  open  position 

The  Webster  Type  W  Modulation  Valve  is  a  special-purpose  radiator 
valve  of  the  quick-opening,  non-rising  stem,  straight-lift  type,  built  for  com- 
plete opening  or  closing  with  less  than  a  single  turn  of  the  handle.  Its 
manipulation  is  as  simple  and  its  control  as  effective  as  the  movement  that 
regulates  light  from  a  gas  jet. 

As  the  names  implies,  the  principal  function  of  the  Webster  Modulation 
Valve  is  to  facilitate  "modulation"  of  temperature  in  each  room  according 
to  the  desires  of  the  occupant,  by  varying  the  amount  of  steam  admitted 
to  the  radiator  or  coil.  A  pointer  attached  to  the  handle  traveling  over  a 
graduated  dial  indicates  the  amount  of  valve  opening  at  all  times. 

With  the  valve  full  open,  the  discharge  capacity  through  the  ports  is 
nearly  equal  to  that  of  the  outlet  connection  of  the  valve. 

Less  than  three-fourths  of  the  valve  lift  and  opening  movement  is  re- 
quired to  produce  modulation  up  to  normal  full  heating  requirement.  The 
rest  is  in  reserve  to  admit  more  steam  during  the  heating-up  period,  as  needed 
to  compensate  for  the  higher  condensation  rate  caused  by  contact  with  the 
cold  radiator  and  its  surrounding  air. 

CONSTRUCTION  DETAILS:  The  modulation  effect  is  produced  by  a  pat- 
ented modulating  plug  which  varies  admission  of  steam  in  progressive  vol- 
ume with  the  lift  of  the  valve  piece. 

A  Jenkins  disc  is  used  to  insure  tight  closing.  With  the  exception  of 
this  and  the  handle,  a!l  parts  are  of  brass.  The  handle  is  of  special  composi- 
tion and  so  formed  that  the  hand  of  the  operator  does  not  come  into  contact 
with  the  heated  surface  of  the  valve  body. 

Application:  The  Webster  Modulation  Valve  may  be  used  on  either 
hot-water  type  radiators  (having  connections  from  section  to  section  at  both 
top  and  bottom)  or  with  steam  type  radiators  (bottom  connections  only), 
although  the  former  type  is  preferable  from  the  standpoint  of  convenience. 

Where  the  Webster  Modulation  Valve  is  used  with  the  hot-water  type 
of  radiator,  it  should  be  placed  at  the  top  to  bring  the  operating  handle  in 

250 


the  most  convenient  location  and  to  permit  the  steam  to  circulate  across 
and  downward.  Air  and  condensation,  being  heavier,  fall  to  the  bottom 
in  advance  of  steam  and  give  full  efficiency  to  the  heated  part  of  the  radiator. 

Where  the  Webster  Modulation 
Valve  is  used  with  a  steam  type  radiator, 
it  is  possible  by  the  use  of  an  inlet  section 
of  the  hot-water  type  to  secure  the  con- 
venience of  operation  which  is  obtained 
where  the  valve  is  placed  at  the  top  of 
the  radiator. 

If  placed  at  the  bottom  of  radiators, 
because  other  connections  cannot  be 
arranged,  the  inlet  bushing  should  be 
eccentric  and  so  located  that  the  center 
line  of  the  radiator  or  inlet  is  above  that 
of  the  radiator  outlet.  This  is  essential 


Fig.  24-18.     Typical  application  of  the  exten- 
sion stem  principle 

to  prevent  condensation  from  drain- 
ing by  gravity  through  the  supply 
instead  of  the  return  connections, 
thus  eliminating  water-hammer. 


WEBSTLR  MODULATION  VALVE 


Wall 


Radiator 


port 


Fig.  24-20.     Typical   appli- 
cation of  chain  attachment  to 
Webster  Type  W  Modulation 
Valve 


Fig.  24-19.    Typical  appli- 
cation   of    chain    attach- 
ment to  Webster  Type  W 
Modulation  Valve 


Floor  Line,,, 


Extension  Stem:  For  attachment  to  radiators  concealed  in  recesses  or 
under  window  seats  behind  grilles,  the  Webster  Modulation  Valve  is  provided 
with  an  extension  stem  and  a  special  dial  that  may  be  placed  on  the  face,  top 
or  end  of  the  grille  or  seat  (see  Figure  24-18). 

The  stem  has  a  universal  joint  on  each  end,  which  permits  operation 
of  the  valve  from  a  point  not  directly  in  line  with  the  valve  stem,  and  at 
the  same  time  provides  enough  play  to  avoid  sticking  or  binding  from  mis- 
alignment or  shifting  caused  by  expansion  and  contraction.  This  con- 
struction also  avoids  the  necessity  for  very  accurate  stem  connections. 

The  outside  indicator  dial,  pointer  and  handle  are  similar  to  those  used 
on  top  of  the  standard  valve. 

Chain  Attachment:  The  Webster  Modulation  Valve  to  be  applied  to 
radiators  or  coils  located  in  skylights,  overhead,  or  on  walls  near  the  ceiling, 
can  be  fitted  with  a  chain  attachment  for  convenience  in  obtaining  every 
advantage  of  the  modulation  feature  (Figures  24-19  and  24-20). 

The  chain  wheel  is  substituted  for  the  handle  of  the  standard  type  of 
Modulation  Valve  and  the  chain  is  made  just  long  enough  to  permit  easy 
grasp  from  the  floor.  Tags  are  attached  to  bottom  of  the  chain  in  such 
positions  that  the  hanging  end  indicates  the  degree  of  valve  opening. 

Table  24-4.    Dimensions  of  Type  W 
Modulation  Valve 


Size 


J* 


V/s 


All  dimensions  in  inches  and  subject  to  slight  variation. 
For  ratings,  see  Table  23-3,  page  237 

The  Webster  Double-service  Valve 

This  is  one  of  the  latest  developments  of  apparatus  for  simplifying 
piping  connections  in  steam  heating  systems  in  certain  types  of  construction. 

Common  practice  in  buildings  of  only  one  story  and  in  some  other 
instances  calls  for  a  steam  supply  line  along  the  ceiling  of  the  first  floor  to 
feed  each  radiator  or  coil  through  a  short  down-feed  riser,  which  must  be 
dripped  into  the  return  line.  This  multiplicity  of  unsightly  connections  is 
simplified  by  the  use  of  Webster  Double-service  Valves,  applied  in  the 
manner  shown  in  Figure  24-23. 

This  valve  performs  "double  service, "  as  a  supply  valve  for  the  radiator 
and  as  a  trap  for  draining  the  riser. 

The  thermostatically  controlled  valve  is  open  when  there  is  water  or  air 
in  the  riser,  and  permits  the  condensate  to  flow  through  a  bypass  in  valve 
body  into  the  radiator  and  thence  into  the  return.  Upon  presence  of  steam 
the  thermostatic  member  expands,  closes  the  valve,  and  thus  prevents 
waste  of  steam. 

252 


Fig.  24-22.     The  Webster  Double-service  Valve 


Supply  Main 


Supply  Riser- 


All  Connections  lo  be  taken 
from  Bottom  of  Main 


Steam  is  admitted   to  the  radia- 
tor in  amount  desired,  by  means  of 
the  quick-opening  valve,  which  is  pro- 
vided with  a  graduated  dial  and  handle. 
This  valve  does  not  include  the  modula- 
tion feature,  as  the  supply  valve  is  designed  only  for 
quick  opening  without  respect  to  modulating  effect. 

The  valve  body  is  best-quality  cast  iron,  and  all 
other  parts  except  the  valve  disc  and  handle  are  brass. 
Nut  and  nipple  are  provided  only  at  one  end  to  promote 
easy  installation.  All  outside  parts  are  nickel-plated. 


WEBSTER 

DOUBLE  SERVICE 

VALVE 


Return  Main. 


Floor  Line 


ntric  Bushing 

WEBSTER 
RETURN  TRAP 


Fig.  24-23.     Application  of  a  Webster  Double-service  Valve  to  a  standard  cast-iron  radiator 

253 


The  thermostatic  member,  which  is  built  up  of  four  discs  of  phosphor 
bronze  and  filled  with  a  volatile  fluid,  the  conical  valve  piece  and  the  sharp- 
edged  seat  are  of  standard  pat- 
tern as  used  in  the  Webster  No.  7 
Trap. 

The  inlet  valve  is  provided 
with  a  ring  seat  and  Jenkins  disc 
to  insure  tight  closing.  Its  quick- 
opening  feature  is  provided  by  a 
screw  stem  of  such  pitch  that  the 
valve  will  be  completely  opened 
with  less  than  a  complete  turn  of 

Fig.  24-24.    The  Webster  Double-service  Valve  handle. 

Table  24-5.     Dimensions  of  Webster  Double-service  Valves 


' 


Size 


2% 


2*A 
3 


8 


10M 


All  dimensions  in  inches  and  subject  to  slight  variation.     For  ratings,  see  page  237 

Webster  Oil  Separators 

The  Series  21  Webster  Oil  Separator  is  made  in  two  patterns — for  either 
horizontal  or  vertical  direction  of  steam  flow.  The  baffles  in  the  horizontal 
type  are  double-hooks  so  that  either  nozzle  may  be  used  as  the  steam  inlet. 
The  vertical  pattern  is  suitable  for  up-flow  of  steam  only. 

An  outstanding  feature  of  this  series  of  Webster  Oil  Separators  is  the 
position  of  the  manhole  cover  which  makes  it  possible  to  inspect  or  clean 
the  device  without  disturbing  the  piping. 

Separation  of  oil  and  condensation  is  effected  by  impact  upon  and 
adhesion  to  baffles  and  by  abrupt  changes  of  direction  of  flow  through  the 
separator. 


Fig.  24-25.     Series  21  Webster  Oil  Separator  Standard  Horizontal  Type 

254 


Fig.  24-26.     Series  21  Webster  Oil  Separator,  Standard  Vertical  Type,  for  upllow  only 

There  is  no  unobstructed  path  through  any  Webster  Oil  Separator, 
yet  the  free  area  through  which  steam  must  pass  is  several  times  greater 
than  inlet  and  outlet  area,  thus  minimizing  pressure  loss  due  to  friction. 

The  use  of  these  separators  pro- 
tects boiler  heating  surfaces  and  inte- 
rior surfaces  of  heating  systems  from T° 
the  oil  deposits  that  otherwise  seriously 


Uliausl 
Main 


WEBSTER  OIL  SEPARATOR 


Exhaust 
Main 


To  Healing  Supply  Main/ 

Size  of  Vent  to  correspond  with  Size 
of  Tapping  in  Top  ot  Grease  Trap 
WEBSTER  GREASE  AND  OIL  TRAP 


Hot  Well 


n 


ize  ot  Vent  to  correspond  with  Size 
I  Tipping  in  Top  ol  Grease  Trap  — 


By  Pass 
Larger  than  Drip  of  Oil  Separator 


1   Free  Vent 

ilfr 


i  Line 


This  Distance  from  Bottom 
of  Oil  Separator  lo  the 
Inlet  ol  Grease  I  rap  must 
be  at  least  Five  Feet  '5'-0'0 


Foundation 


Fig.   2-1-27.     Method  of  connecting  a  Webster  Grease  Fig.  2 1-28.   Typical  method  of  draining  Webster 
Trap  to  a  Webster  Oil  Separator,  where  a  partial  Oil  Separator  through  a  Webster  Grease 

vacuum  may  at  times  be  carried  on  the  Trap,  where  positive  pressure  is  main- 

heating  main  tained  at  all  times 

impair  heat  transmission  and  often  cause  serious  damage. 

These  separators  may  also  be  used  for  such  special  purposes  as  removing 
moisture  or  oil  from  compressed  air  and  other  gases. 

That  Webster  Separators  are  efficient  in  all  their  standard  and  special 
forms  is  indicated  by  absolute  satisfaction  in  over  15,000  installations. 

255 


The  material  ordinarily  used  in  the 
shells  is  close-grained  cast  iron,  but  spe- 
cal  shell  of  semi-steel,  cast  steel  or  other 
material  can  be  furnished  at  extra  cost. 

Table  24-6.  Maximum  Ratings  of  Oil  Sepa- 
rators in  Lb.  per  Min.  at  Average  Gauge  Pres- 
sures Based  on  6000  Ft. per  Min.Pipe  Velocity 


^Outlel 


Size 


Pressure,  Ib.  per  sq.  in. 

5  10 


2 

5.2 

6.7 

8.4 

10. 

3 

11.4 

15. 

18.6 

22. 

4 

19.8 

26. 

32. 

38. 

5 

31. 

40.6 

50.2 

59.7 

6 

45. 

59. 

73. 

86.5 

8 

78. 

102. 

126. 

150. 

10 

123. 

160. 

200. 

235. 

12 

176. 

231. 

285. 

339. 

14 

222. 

292. 

361. 

427. 

16 

294. 

385. 

475. 

565. 

18 

375. 

492. 

608. 

720. 

20 

452. 

595. 

735. 

870. 

22 

550. 

725. 

900. 

1060. 

24 

660. 

870. 

1070. 

1270. 

For  lower  velocities,  the  pounds  carried  will  be  propor- 
tional as  the  lower  velocity  is  to  6000  p-     24-30 

Table  24-7.    Dimensions  of  Webster  Oil  Separators 

All  dimensions  in  inches.     Companion  flanges  furnished  only  on  special  order;  drilled 

low-pressuse  standard  unless  otherwise  ordered 
Standard  Horizontal  Type  (Fig.  24-30) — for  steam  flow  in  either  direction 


Dimensions 


Flanges 


SIZE 


4 

5 

6 

8 

10 

12 

14 

16 


B 


10 

10M 

12 


15 


19 
21 

22 
24^ 
28 
31 


16 


22 
25  M 


5Ji 
6 


6 

6*A 


ioy2 

13  * 


Drip 


1 
1 
1 
1 

l¥ 

2 

9 


Outside 
diameter 


9 
10 
11 


16 
19 
21 

23^ 


Bolt 
circle 


14M 
17 


21  J< 


No.  &  sizes 
of  bolts 


4-^g 

4-H 


12- Ji 
12-  1 
16-  1 


*Screw  connections  only.      Standard  Vertical  Type  (Fig.  24-29)— for  up-flow only 


Dimensions 

Flanges 

SIZE 

B 

D 

E 

H 

Drip 

Outside 
diameter 

Bolt 
circle 

No.  &  sizes 
of  bolts 

3 

13*4 

iy& 

sy2 

7% 

M 

iy2 

6 

4-5/s 

3^2 

14^i 

8% 

4 

9 

H 

8/4 

7 

4-41 

4 

16 

9/^8 

4/^ 

10J^ 

i 

9 

1]/z 

8-J^ 

5 

16^4 

12 

5y% 

127A 

i 

10 

%y2 

8—^4 

6 

18 

15J4 

(>*A 

15k 

i 

11 

91A 

8—  M 

8 

20^ 

ny2 

8J4 

1M 

13Ji 

11% 

8-% 

10 

22  }4 

21N 

10J^ 

25 

16 

14J4 

12-  ^ 

12 

24 

24% 

ll/^ 

29^ 

2 

19 

17 

12-% 

14 

25  *A 

2S*A 

135^ 

33^ 

2 

21 

18^ 

12-  1 

16 

28 

15% 

2H 

233^ 

21M 

16-  1 

256 


Webster  Low-pressure  Receiver  Oil  Separators 

These  separators,  acting  as  eliminators  of  oil  and  condensation  and  as 
receivers  or  mufflers,  are  used  chiefly  in  exhaust  steam  lines  between  recipro- 
cating engines  and  low  or  mixed-pressure  turbines,  or  as  receivers  for  the  in- 
termittent exhaust  from  groups 
of  steam  hammers. 

They  are  of  riveted  steel  con- 
struction, with  cast-iron  nozzles, 
and,  like  most  of  the  Webster  Oil 
Separators,  are  equipped  with 
hooked  steel  multi-baffles.  The 
nozzles  are  of  cast  iron  with  flanges 
drilled  low-pressure  standard. 

The  illustration  shows  one  of 
the  many  forms  of  the  Webster 
Low-pressure  Receiver  Oil  Sepa- 
rator. The  inlet  and  outlet  noz- 
zles may  be  located  to  conform 
with  any  direction  of  flow  of 
steam.  The  axis  of  the  shell  may  be  either  horizontal  or  vertical. 

Inquiries  regarding  the  Webster  Low-pressure  Receiver  Oil  Separators 
should  be  accompanied  by  a  sketch  showing  the  proposed  -location  of  and 
space  available  for  the  separator,  the  sizes  and  locations  of  inlet  and  outlet 
nozzles  and  the  direction  of  flow.  The  inquiry  should  state  the  maximum 
amount  of  steam  to  be  purified. 

Webster  Grease  and  Oil  Traps 


Fig.  24-31.    The  Webster  Low-pressure  Receiver  Oil 
Separator 


Fig.  24-32.    The  Webster  Grease  and  Oil  Trap 

The  Webster  Grease  Trap  is  for  use  in  draining  oil  separators  on  exhaust 
steam  lines  or  on  feed-water  heaters,  or  for  removing  from  the  course  of  the 
steam  any  accumulations  of  oily  drips  at  other  points  in  the  low-pressure 
steam  mams  or  branches.  It  will  operate  with  equal  efficiency  under  any 
pressure  between  atmospheric  and  15  Ib.  per  sq.  in.,  above.  It  is  not  de- 
signed for  use  under  high  vacuum  conditions. 

As  shown  in  the  accompanying  sectional  illustration  (Figure  24-32)  the 
valve  mechanism  is  simple.  The  discharge  orifice  is  designed  to  give  the 
full  area  of  the  inlet  opening.  The  valve  piece  is  conical  and  closes  against 
a  sharp-edged  seat. 


257 


The  ball  float  and  valve  chamber  are  easily  reached  for  quick  cleaning 
without  disturbing  pipe  connections. 

Properly  installed,  the  Webster  Grease  Trap  should  be  provided  with  a 
bypass  in  the  piping  around  it;  a  check  valve  should  be  in  the  line  beyond 
the  outlet  and  bypass,  and  an  equalizing  or  vent  pipe  should  be  run  from 
the  top  of  trap  to  the  exhaust  main  beyond  oil  separator.  See  Figure  24-28. 
PLATINGS  FOR  WEBSTER  GREASE  TRAPS:  Because  the  mixture  to  be 
discharged  is  likely  to  be  more  or  less  viscous  and  sluggish  in  movement 

when  it  is  cool  it  is  impossible  to  rate  grease 
traps  on  a  condensation  basis.  The  size  of 
grease  trap  to  be  selected  in  any  case  should 
be  that  of  the  drip  connection  of  the  oil 
separator  which  it  is  to  drain. 

Table  24-8.    Dimensions  of  Webster  Grease  and 
Oil  Traps 


Number 


016 
116 
216 


A'  Size  Outlet  A=Size  Inlet 

Fig.  24-33 


A' 


B 


15M 
19V* 
20Ji 


15 


3V* 


2J/8 


8V*6Vi 


8 


w 


H 


All  dimensions  in  inches  and  subject  to  slight  variation 


The  Webster  Suction  Strainer 


Fig.  24-34.    The  Webster  Suction  Strainer 


The  Webster  Suction  Strainer  is  used  to  prevent  the  passage  to 
the  vacuum  pump  of  dirt  and  scale  brought  down  with  the  condensation 
from  a  vacuum  heating  system.  The  use  of  this  strainer  prevents  scoring 
of  the  pump-cylinder  lining,  valves  and  piston  rods  and  the  serious  efficiency 
losses  and  repair  bills  that  would  follow  such  scoring.  The  strainer  is  pro- 
vided with  a  tapping  for  the  introduction  of  cold  make-up  water  when  same 

258 


is  desired  and  when  specially  ordered,  a  spray  nozzle  is  provided  to  insure 
thorough  mixture  of  cold  water  and  vapor  in  return.  Another  tapping  is 
provided  for  a  connection  to  the  vacuum  gauge  and  a  third  plugged  outlet 
is  for  draining  the  body  when  the  strainer  is  not  in  use.  The  shell  and  re- 
movable cover  are  of  cast  iron  with  composition  gasket  in  the  joint.  Com- 
panion flanges,  drilled  low-pressure  standard,  are  provided  for  inlet  and  out- 
let connections. 

The  basket  is  of  perforated  brass,  and  has  at  its  top  rim  a  casting  in 
which  is  fastened  a  handle  for  h'fting  out  the  strainer.  The  perforations  are 
0.043  in.  in  diameter  and  of  sufficient  number  to  provide  a  total  area  twice 
that  of  the  entering  pipe. 

The  Webster  Suction  Strainer  is  to  be  placed  in  horizontal  piping  only, 
and  should  be  set  so  that  the  axis  of  the  body  will  be  vertical.  Water 
flows  to  it  in  the  direction  of  the  arrow  (see  Figure  24-34),  and  its  course 
through  the  strainer  is  evident  from  the  sectional  view  in  the  same  figure. 

During  the  cleaning  process  it  is  customary,  if  the  system  must  be  main- 
tained in  operation,  to  use  either  the  relay  pump  or  the  ejector,  if  there  is 
one,  and  if  not,  to  temporarily  run  the  returns  by  gravity  to  the  sewer  or 
waste,  closing  the  stop-valve  in  the  main  return.  The  entire  operation  oc- 
cupies but  a  few  minutes. 

Table  24-9.    Dimensions  of  Webster  Suction  Strainer 


K-  No.  and  Size  Bolls 


For  maximum 

working  pressure 

of  15  Ib.  per 

sq.  in. 


Fig.  24-35  Top  view 

All  dimensions  in  inches  and  subject  to  slight  variation 


N  Tapped  and  Plugged 
'-C- 


Size  A 


B> 


2 

3 

4 

5 

6 

7 

8 

10 

12 


IP 

ioi| 

14p 
21  * 


% 

11J4 


12 

1(,34S 


20  Ji 
25 

27  K 


38 


10 
11 


16 
19 


13 


21 

24J^ 
29 


13 


20 


10?4 
11M 
14K 
17 


4-^x|i 
8-^|x2M 


S-Kx2% 
8-?ix3 


X 


Webster  Dirt  Strainers 

Webster  Dirt  Strainers  are  used  in  steam  heating  systems  to  prevent 
dirt  from  entering  radiator  traps  or  traps  on  drip  points,  mains  or  blast 
coils.  They  provide  convenient  receptacles  for  retention  and  accumulation 
of  pipe  chips,  rust,  dirt,  etc.,  where  impurities  can  do  no  harm  and  where 
they  are  easily  and  quickly  removed. 

259 


Fig.  24-36.     Class  A  (Offset) 


Webster  Dirt  Strainers 


Fig.  24-37.     Class  B  (Straightway) 


Two  models  are  made:  Class  A  with  offset  and  Class  B  with  straight- 
way pipe  connections.  Both  have  cast-iron  shell  and  cover,  the  latter  made 
easily  removable  by  means  of  a  yoke  and  screw. 

The  basket  is  made  from  sheet  brass  perforated  with  0.043-in.  diameter 
holes.  The  total  free  area  through  the  basket  is  several  times  the  area  of 
the  entering  pipe.  The  sides  of  the  basket  are  reinforced  with  strips 
which  are  continued  upward  to  form  a  bale  handle.  This  handle  not  only 
serves  to  make  the  basket  easily  removable  but  acts  as  a  spring  against 
the  cover  to  hold  the  basket  in  place. 

The  range  of  types  and  sizes  offers  a  selection  for  any  service  conditions. 

The  use  of  these  strainers  greatly  lessens  the  amount  of  attention  re- 
quired to  keep  the  system  in  thoroughly  efficient  operation  and  eliminates 
incentive  for  the  neglect  always  to  be  expected  with  dirt  pockets  composed 
of  pipe  fittings,  which  cost  nearly  as  much  to  make  and  are  never  as  good. 

Table  24-10.    Dimensions  of  Webster  Dirt  Strainers,  Classes  A  and  B 
Maximum  pressure,  15  Ib.  per  sq.  in. 

Dimensions  in  inches  and  subject  to  slight  variation  Class  A. — Offset  (Fig.  24-38) 

Class  A 


Class  B 


No. 


Size  A 


B 


018-Al  K< 
118-A1  < 
218-AlKor2  6 


B' 


2% 


B"    C 


2H 


H 


2H 

VAVA 


Class  B.— Straightway  (Fig.  24-39) 


No. 


018-B 
118-B 
218-B 


Fig.  24-38 


Fig.  24-39 


Size  A 


y20r 

1      or  1 

IK  or  2 


B' 


6% 


4M 


The  Webster  Vacuum-pump  Governor 

The  vacuum  pump  of  a  vacuum  heating  system  should  be  as  nearly 
automatic  in  operation  as  possible. 

The  Webster  Vacuum-pump  Governor  automatically  controls  the  admis- 
sion of  steam  to  the  pump  cylinder  or  cylinders  in  proportion  to  the  degree  of 
vacuum  required.  When  only  part  of  the  heating  load  is  on,  just  enough 

260 


steam  is  admitted  into  the  pump  to  produce  the  degree  of  vacuum  required. 

When  the  need  is  greater,  the  supply  of  steam  is  automatically  increased. 

The  Webster  Vacuum- 
pump  Governor  can  be  ad- 
justed to  control  the  vacuum 
to  any  predetermined  degree, 
and  may  be  readjusted  when 
necessary.  It  is  remarkably 
sensitive  through  a  wide  range 
of  adjustment. 


The  Webster 

Vacuum-pump 

Governor 


Size  A 


24-40  Fig.  24-41  Fig.  24-42 

Table  24-11.     Dimensions  of  Webster  Vacuum-pump  Governors 


Size  A 


B> 


6% 
8 


IK 
IK 

** 
1M 
IK 
IK 
IK 


9Ji 
9Ji 
9Ji 
9J^ 
9Ji 
9^ 

9M 


8 

sll 


11 


lltt 

12 


2 
2 
2ft 


23 
24 


26 
28 


30 


The  Webster  Suction  Strainer  and  Vapor  Economizer 

This  special  device,  in  addition  to  its  function  of  protecting  the  vacuum 
pump,  has  a  particular  advantage  in  vacuum  heating  systems  where  some 
unusual  operating  condition  results  in  the  return  of  water  to  the  vacuum 
pump  at  a  high  temperature. 

Under  such  conditions,  re-evaporation  or  transformation  of  water  into 
steam  vapor  may  occur,  and  the  presence  of  this  steam  vapor  adds  to  the 
duty  of  and  may  interfere  with  the  proper  operation  of  the  pump. 

If  cold  water  is  constantly  required  for  making  up  the  boiler-feed  water 
it  can  be  introduced  in  the  standard  Webster  Suction  Strainer,  by  the  use 


261 


of  the  Webster  spray-head,  without  increasing  the  cost  of  plant  operation. 
The  special  Webster  Suction  Strainer  and  Vapor  Economizer  is  designed 
to  meet  conditions  where  cooling  water  is 
required,  but  where  the  use  of  it  as  make- 
up water  would  entail  waste. 

The  cold  water  is  passed  around  a 
nest  of  copper  coils  and  absorbs  the  heat 
of  the  steam  vapor  in  the  main  return. 

This  water  is  not  handled  by  the 
vacuum  pump  and  does  not  mix  with  the 
condensation  in  the  main  return  line,  as 
the  economizer  becomes  merely  an  ex- 
tension of  the  hot- water  piping  system, 
under  the  available  pressure. 


Fig.  24-43 


Fig.  24-44.     The  Webster  Suction  Strainer 
and  Vapor  Economizer 


Table  24-12.     Dimensions  of  the  Webster  Suction  Strainer  and  Vapor 

Economizer 

AH  dimensions  in  inches  and  subject  to  slight  variation 


Size  A 


U          M 


28^ 


22          10 
31 3/s 


187/8     10 
24^ 


12 
19 


ii      8-M  x  3 


78 


1A 


262 


Fig.  24-45. 
Webster  Lift  Fitting 


Webster  Lift  Fittings— Series  20 

Webster  Lift  Fittings  are  special  devices  used  in 
pairs  at  points  in  vacuum  heating  systems  where  con- 
densation is  to  be  lifted  to  a  higher  level.  The  con- 
densation is  lifted  vertically  to  a  higher  level  in 
"slugs"  on  the  air-lift  principle;  the  slugs  being  ob- 
tained by  the  use  of  a  comparatively  small  diameter 
vertical  return  with  its  lower  end  submerged  in  the 
well  below  the  level  of  the  horizontal  return  which  it 
drains.  The  lower  lift  fitting  allows  the  condensa- 
tion to  accumulate  in  the  well  below  the  inlet  connec- 
tion until  it  seals  the  vertical  passage,  thus  causing 
a  slight  reduction  of  the  vacuum  on  the  inlet  side  and 
forcing  the  water  from  the  well  through  the  vertical  lift  pipe  to  the  higher 
level.  The  upper  lift  fitting  allows  the  condensation  to  flow  into  the 
horizontal  return  without  falling  back  into  the  lifting  line. 

Lifts  of  six  feet  or  over  should  be  made  in  steps  rather  than  all  in  one 
rise.  Steps  should  be  used  instead  of  "drag"  lifts  through  long  upwardly 
inclined  pipes.  In  any  case,  the  pipes  between  lifts  must  grade  toward  pump. 

Webster  Lift  Fittings  are  a  big  improvement  upon  and  should  be  sub- 
stituted for  the  home-made  fittings  which  in  the  past  have  had  to  be  made 
from  combinations  of  ordinary  tees  or  crosses  and  plugs,  because  nothing 
better  was  obtainable.  Each  Webster  Lift  Fitting  is  a  unit  casting,  neat  in 
appearance  and  correctly  proportioned  for  capacity  of  well  and  for  the  area 
ratio  of  inlet  to  outlet.  The  use  of  these  fittings  eliminates  all  the  guess- 
work and  uncertainty  about  proper  operation.  They  cost  less  than  combi- 
nations of  fittings  when  the  labor  cost 
as  well  as  that  of  the  fittings  is  con- 
sidered. 

Each  fitting  is  provided  with  a 
clean-out  plug  for  removing  any  accu- 


Line 


Fig.  2t  -If). 

Typical  application  of  Webster  Lift  Fittings 
(See  also  Fig.  13-1,  page  139) 


Fig.  24-47. 
Long  screwed 
lift  connection 


Fig.  24-48. 

Ix>ng  flanged 

lift  connection 


263 


mulation  of  dirt  or  other  foreign  matter  from  the  lift  pocket.    The  larger 
sizes  are  flanged  and  finished  and  drilled  to  the  low-pressure  standard. 


r~ 


Fig.  24-49 

Table    24-13.      Dimensions    of    Series 
Webster  Lift  Fittings  in  inches 


20 


Inlet  Outlet 


Close  screwed  Close  flanged 

litt  connection  lift  connection 

Fig.  24-50 

Table  24-14.    Minimum  Distance  Between 
Centers 


Size 


3 

4 

5 

6 

8 

10 

12 


Screwed 


Flanged 


3 

i 

5 
(. 
8 

10 

12 


3K19^ 


31^20J4 
34K  22% 


12« 
14A 
17 

20% 
23  A 


Drain 


%-in.  screwed  fittings          A  = 

3}^  in. 

1-in. 

A  = 

31^  in. 

lJ4-in. 

A  = 

4i/g  jn- 

IK-in. 

A  = 

4%  in. 

2-in. 

A  = 

5K  in. 

2^-in. 

A  = 

8  in. 

3-in.  flanged  fittings               B 

=  10A  |n. 

4-in. 

B 

=  13A  in. 

5-in. 

B 

Sin. 

6-in. 

B 

in! 

8-in. 

B 

=  ISA  in. 

10-in. 

B 

=  22A  in. 

12-in.                                           B 

=  23f£  in. 

Webster  Receiving  Tanks— Plain,  Water-control 
and  Steam-control  Types 

These  tanks  are  used  in  connection  with  vacuum  steam  heating  systems, 
to  provide  a  place  for  storage  of  the  condensation  discharged  by  the  vacuum 
pump  and  for  liberation  of  the  air  that  comes  over  with  this  condensation. 
Each  type  is  designed  for  pressures  not  exceeding  30  Ib.  per  sq.  in.,  for 
installation  in  horizontal  position,  and  each  type  has  proper  receiving 
capacity  and  air-liberating  surface. 

The  Plain  Type  receives  the  condensation  and  air  through  an  end 
opening  near  the  top.  The  air  escapes  through  a  vent  in  the  top  of  the  tank, 
and  the  water  flows  by  gravity  to  the  bottom  outlet  and  to  the  feed-water 
heater  or  other  point  of  disposal.  If  the  rate  of  flow  of  returns  to  tank  ex- 
ceeds rate  of  discharge  from  tank,  the  excess  overflows  through  an  opening 
on  the  end  near  the  top. 

The  Water-control  and  Steam-control  Types  have  regulating  valves 
which  are  operated  by  sink  pan  and  rigging  similar  to  those  used  to  regulate 
the  water  level  in  Webster  Feed-water  Heaters.  These  two  types  are  also 
provided  with  water-troughs,  to  insure  best  operation  of  the  sink  pan. 

The  Water-control  Type  has  its  regulating  valve  arranged  to  automati- 
cally admit  "make  up  "at  all  times  when  the  returns  from  the  heating  system 
are  temporarily  insufficient  to  keep  the  water  level  in  the  tank  at  the  pre- 


264 


Fig.  24-52.  Webster  Air-separating 

Tank  and  Receiver,  Steam-control 

Type 


Fig.  24-51.    Webster  Air-separating 

Tank  and  Receiver,  Water-control 

Type 


determined  point.  The  air  is  vented  to  atmosphere,  the  water  flows  by 
gravity  to  the  heater  or  other  place  of  disposal,  and  any  excess  of  water 
overflows,  as  with  the  Plain  Type. 

The  Steam-control  Type,  which  is  used  where  the  boiler  or  boilers  are 
to  be  fed  in  proportion  to  the  returns  reaching  the  receiving  tank,  has  its 
regulating  valve  installed  in  the  steam  supply  fine  to  the  boiler-feed  pump. 
With  water  in  the  tank  at  or  above  the  predetermined  level,  the  boiler-feed 
pump  is  in  operation,  feeding  the  returns  into  the  boiler,  but  when  the  tank 
level  is  below  normal,  the  steam  to  the  boiler-feed  pump  is  shut  off  and  the 
pump  stopped  until  sufficient  returns  collect  again.  Make-up  water,  if 
necessary,  may  be  introduced  into  the  tank  by  hand.  The  venting  of  air 
to  atmosphere,  delivery  of  water  by  gravity  flow  and  provision  for  overflow 
of  excess  water  are  the  same  as  in  the  Plain  Type. 

All  three  types  of  Webster  Receiving  Tanks  are  made  from  riveted 
flange  steel  and  have  flat  heads.  The  Water-control  and  Steam-control 
Types  have  removable  manhole  covers  and  gauge  fittings  in  one  end.  Each 
tank  is  hand-made  throughout  from  best  obtainable  materials.  The  sizes 
listed  are  standard.  Larger  sizes  can  be  made  upon  special  order. 

265 


Table  24-15.     Dimensions  of  Webster  Receiving  Tanks 
Note:  Openings  will  be  bushed  to  suit  requirements.     All  dimensions  in  inches 


Plain 
Type 


Fig.  24-53 


Overflow 


v  Outlet 


Size 


Inlet 


Outlet 


Air  vent 


Overflow 


18x48 

4 

4 

IJi 

4 

25H 

25 

3>i 

24x72 

5 

5 

2 

5 

38% 

37 

6 

36  x  96 

8 

8 

3 

6 

so* 

49 

ll^i 

Water- 
control 
Type 


Fig.  24-54 


Manhole 


Size  Inlet      Outlet      Air  vent  Overflow  Reg.  valve       A 


D 


E 


18x48  4 

24  x  72          5 
36  x  96          8 


50^ 


12  24^       14 

18          36M      18 
18          485^      24 


23 


Steam- 
control 
Type 


Fig.  24-55 


-D *\   Pump  Governor  Valve 

/ 

B- 


Overflow 


lanhole 


Size  Inlet      Outlet     Air  vent  Overflow  Gov.  valve        A 


D 


E 


18x48  4 

24  x  72          5 
36  x  96  8 


13/2 

2 

3 


1  25^2 
1J$      37^ 

2  50M 


30J/2       'AYz 
42}4      6 
54^-g     11H 


12  24}^       14 

18          36^      18 
18  48Ji       24 


23 


For  ratings  see  Table  13-1,  page  138 
•2fi6 


The  Webster  Water  Accumulator 


Fig.  24-56.    The  Webster  Water  Accumulator 

This  is  a  cast-iron  fitting  of  oval  cross  section,  designed  to  accumulate 
condensation  for  the  protection  of  the  diaphragms  of  pressure-reducing 

WEBSTER 
Bypass  »ith  Globe  or  Angle  Valve  WATER  ACCUMULATOR  X  Tee  lor  Gauge  Connection 

"^=H      p 


Live  Steam  from  Boiler 


Straight  Pattern  Pressure 
Reducing  Valve 


Provide  Pel  Cock  for  Venting  Diaphragm 
^Connect  to  Receiver 


•/i'  Pop  Safety  Valve 


Plugged  Tee 


Fig.  24-57 


valves  and  similar  appa- 
ratus against  the  heat  of 
steam  which  would  de- 
teriorate the  diaphragms 
if  brought  into  direct  con- 
tact. This  application  is 
shown  in  Figure  24-57. 

The  Webster  Water  Accumulator  may  also  be  used  to  provide  protec- 
tion for  low-pressure  steam  gauges. 


Fig.  21-58 


Fig.  '2 1-.)9.     Webster  Combination  Gauges 

Gauges  for  Webster  Systems 

Webster  Gauges  are  of  high  quality  and  are  furnished  in  various  stand- 
ard forms,  and  to  suit  special  specifications.  The  usual  outfit  furnished 
with  Webster  Vacuum  Systems  is  a  set  of  two  5^-in.  face,  nickel-plated 
combination  pressure  and  vacuum  gauges,  mounted  on  Monson,  Me.,  slate 
board  with  Webster  System  name  plate. 

267 


/Connect  to  Low-pressure  Heating  Main  not  less  than  15  0 
distant  from  Pressure-regulating  Valve 


Single  combination  gauges 
can  be  furnished,  either  for 
Vacuum  or  Modulation  Systems, 
in  5^/2-in.  size. 

Single  gauges  are  also  fur- 
nished with  Webster  Hylo  Vacu- 
um Sets,  as  elsewhere  described. 

Larger  gauges,  slate  or  mar- 
ble boards  for  three  or  four 
gauges,  or  gauges  having  special 
graduations  or  marking  can  also 
be  furnished  when  required. 

The  Webster  Modulation 
Vent  Trap 

This  device  is  installed  in 
the  low  point  of  the  dry-return 
line  of  the  Webster  Modulation 
System  before  the  returns  flow 


to   the    boiler  Or  boilers   as  feed  Fig.24-60.    Connections  for  gauges,  Webster  Vacuum  System 


Globe  Valve^^ 
3/J  x  s/Vxi/Jlee 


As  deep  as  possible 
not  less  than  4'0B 


From  WEBSTER 
VACUUM  GOVERNOR 


3/4  x  3/4  x  1/2  Tee 
•3/J  Dirt  Pocket 
Cap 


Ceiling  Line 


Overhead  Return 
from  Heating  Steam 


By-Pass  required  only  Iwhen 
the  Return  is  larger  thanl 
the  Inlet  to  the  Vent  Ijrap' 


WEBSTER  MODULATION  VENT  VALVES 


Plug,  if  Inlet  Connection 
is  not  used 


WEBSTER  MODULATION 
VENT  TRAP 


This  Distance  must  not 
be  less  than  30  Md  as 
much  more  as  possible 
depending  on  Local 
Conditions 


This  Connection 

must  be  on  same 

Centre  as  Wet  Return 


Connect  into  Wet 
Return  Main 


Wet  Return  near  Floor 


Floor  Line 


Fig.  24-61 .     Typical  installation  of  the  Webster  Modulation  Vent  Trap 

268 


Fig.  24-62.    The  Webster  Modulation  Vent  Trap 

water.  It  affords  a  simple,  dependable  method  of  venting  the  entrained  air 
to  atmosphere  and  of  automatically  insuring  the  return  of  the  water  to  the 
boiler  under  fluctuating  boiler  pressures.  The  air  vent  is  controlled  by  an 
internal  float  mechanism.  The  valve  piece  is  conical  and  closes  against  a 
sharp-edged  seat. 


Overhead  Return  from 
Healing  System 


WEBSTER  MODULATION  VENT  VALVE 


Install  Trap  so  that  Interior  can 
be  removed  from  Bottom 


This  Distance  must  not  be  less 
than  30-'and  as  much  more  as 
possible  depending  o 
Conditions 


This  Connection  must  be  on  same 
Centre  as  Wet  Return 


Floor 


Fig.  24-63.    Typical  installation  of  Webster  Modulation  Vent  Trap  No.  0020 

269 


Other  means  for  returning  water  to  the  boiler  are  provided  for 
unusual  structural  features  of  the  building  or  conditions  of  use,  but  for 
the  average  building  to  which  the  Webster  Modulation  System  is  adaptable 
the  Webster  Modulation  Vent  Trap  is  used. 

In  the  illustrations,  Figures  24-61  and  24-63,  Webster  Modulation 
Vent  Valves  are  shown  in  position  at  the  air  outlets  of  the  Vent  Traps. 
These  valves  are  always  required  where  it  is  desired  to  circulate  steam 
below  atmospheric  pressure  at  intervals.  Where  large  hot-water  genera- 
tors are  used,  or  where  a  part  or  all  of  the  radiators  are  under  automatic 
control,  the  vent  valves  should  be  omitted  unless  vacuum  breakers  are 
provided  on  the  return  lines  at  the  proper  places. 

The  type  of  Modulation  Vent  Trap  shown  in  Figures  24-61,  24-62  and 
24-64  is  that  which  is  used  for  the  larger  systems.  For  installations  such  as 
small  residences,  the  size  0020  Trap  as  shown  in  Figures  24-63  and  24-65 
is  most  often  used.  Capacity  ratings  are  given  on  page  240. 


A-Size  of  Vent  to  Air 

AS-Size  of  Returns  Irom  Heating  System 

- 


NotevGauge  Glass  furnished 
!  L J  on  order  only 

<f*A'-Sizeto  Boiler 

Fig.  24-64.     Dimensions  of  Webster  Modulation 

Vent  Trap,  Series  20 

(See  Table  24-16) 


Fig.  24-65.     Dimensions  of  Webster 

Modulation  Vent  Trap 

Number  0020 


Table  24-16.    Dimensions  of  Webster  Modulation  Vent  Traps,  Series  20,  Fig.  24-64 


SIZE 


B 


B' 


No.  020 
No.  120 
No.  220 
No.  320 


'2 


1 
IK 

IX 
IX 


f>7A 
9A 
9* 


6% 
8 
8 
8 


co  eo  co  en 

W\fcKt^\ri\ 


8M 


10 

MX 

1VA 
15H 


The  Webster  Modulation  Vent  Valve 
This  valve  has  been  specially  devised  to  meet  the 
requirement  for  check  against  inflow  of  air  to  a  modula- 
tion system  when  it  is  desired  to  operate  at  a  pressure 
less  than  atmospheric.  This  check  is  provided  by  the 
seating  of  a  hollow  seamless  ball  which  is  retained  by  a 
cage  structure  as  shown  in  Figure  24-66. 

Due  to  the  very  slight  weight  of  the  ball  and  the 
construction  of  the  valve  body  and  seat,  a  pressure  less 
than  one  ounce  per  square  inch  will  serve  to  lift  the  valve 
Webster    from  its  seat,  thus  permitting  the  escape  of  air  from  the 

Ygjj^  Trap. 

The  Modulation  Vent  Valve  is  made  in  only  the  J^-in.  size  which 

270 


Fig.  24T66. 

Modulation  Vent  Valve 


may  be  used  as  a  single  unit  for  installations  up  to  8500  sq.  ft.  of  direct 
radiation  or  equivalent.  For  larger  installations  these  valves  are  furnished  in 
multiple  units  of  the  necessary  number  with  a  fitting  such  as  that  shown 
in  Figure  24-67.  See  Table  23-9,  page  240. 


"2"  Pipe 
Threads 


For  use  where  two  vent  valves 
are  required 

Fig.  24-67.  Multiple-unit  Webster  Modulation   Vent  Valves 

The  Webster  Damper 
Regulator 

The  Webster  Damper  Regulator 
is  used  with  the  Webster  Modulation 
System  and  automatically  controls  the 
opening  of  the  draft  door  and  check 
damper  of  the  low-pressure  steam  - 
heating  boiler.  It  is  extremely  sensi- 


'/2"Pipe 
IThreads 


Three-valve 
pattern 


Note: -To  support  Damper  Regulato 
use4-Vi"Rods  with  Pipe 
Separator  and  mike  Icngt 
to  suit  work,  remove 
any  4  Bolts  to  suit 


'Asbestos  Disc 


Drain  Pluoged 


^"Connection  to  Live 
Steam  Main 

Fig.  24-69. 
Dimensions  of  the  Webster  Damper  Regulator 


Fig.  2  1-68.    The  Webster  Damper  Regulator 

tive  and  accurate  because  of  the  ample  diaphragm  area  and  controls  the  fire 
to  maintain  the  steam  pressure  always  within  a  few  ounces  of  that  for  which 
the  regulator  is  set. 

Table  24-17.     Power  Developed  by  Webster  Damper  Regulator 

The  following  figures,  based  upon  tests  with  lever  in  mid-position,  afford  a  comparison  with  other 
damper  regulators  having  much  smaller  diaphragms 

Pressure  in  Ib.  per  sq.  in  .....................      0.5  1.0  2.0  3.0  4.0  5.0 

Average  pull  at  end  of  lever,  Ib  ...............  4.125  8..°5  16.5  24.75  33.0  41.23 


271 


Webster  Hylo  Vacuum-control  Sets 

Each  Webster  Hylo  Set  consists  of  a  Webster  Hylo  Vacuum  Con- 
troller, handling  vapor  and  air  only,  a  Webster  Hylo  Trap,  handling  water 
of  condensation  only,  Webster  Hylo  Vacuum  Gauges,  and  when  needed, 
Webster  Lift  Fittings. 

The  Webster  Hylo  Vacuum  Controller  regulates  the  vacuum  from  the 
low  to  the  high  vacuum  through  the  action  of  the  diaphragm  and  pilot 
valve.  The  vacuum  differential,  as  fixed  by  the  position  of  the  weights  on 
the  diaphragm  lever,  may  be  adjusted  to  maintain  the  desired  vacuum. 

The  Webster  Hylo  Trap  permits  condensation  to  flow  from  low  to 
high  vacuum  without  loss  of  differential.  This  trap  is  of  ball-float  type,  with 
outlet  water  sealed. 

The  Webster  Vacuum  Gauges  indicate  the  vacuum  conditions  upon 
both  sides  of  the  controller.  Special  arrangements  of  gauges  and  boards 
are  furnished  for  varying  requirements. 

Webster  Lift  Fittings  are  required  where  returns  must  be  lifted  such 
as  the  case  shown  in  Figure  15-7,  page  177. 


Fig.  24-70 


Table  24-18.    Dimensions  of  Webster 
Hylo  Controller 

All  dimensions  in  inches  and  subject  to 
slight  variation 


»'  Size  Openina  A-Size  Inlet 

Fig.  24-71 

Table  24-19.     Dimensions  of  Webster 

Hylo  Traps  for  15-lb.  Working 

Pressure 

All  dimensions  in  inches  and  subject  to  slight 
variation 


Number 


|Size  A 


—  /"± 

2Ys 


016 
116 
216 


10 


A' 


IJi 


1SA 


15 


4V*3V*2J* 


VA&A 


w 


The  ratings  are  the  same  as  for  Webster  Heavy- 
duty  Traps,  as  given  in  Table  23-80,  page  239 


272 


The  Webster  Sylphon  Conserving  Valve 


Fig.  24-72.  The  Webster 

Sylphon  Conserving 

Valve 


This  valve  is  one  of  the  special  devices  used  in  connection  with  the 
Webster  Conserving  System  where  steam  is  furnished  direct  from  low-pres- 
sure heating  boilers  which  are  required  to  supply  steam  for  other  purposes 
than  warming  the  building,  at  a  constant  pressure  above  that  required  for 
the  heating  system  alone.  It  also  insures  the  constant  operation  of  the 
low-pressure  steam-driven  vacuum  pump. 

It  is  placed  in  the  main  steam  line  from  boiler,  the  steam  connection  to 
vacuum  pump  being  taken  from  the  inlet  side  of  the  conserving  valve.  The 
pressure  for  which  the  conserving  valve  is  set  must  be  built  up  on  the  inlet 
side,  before  the  conserving  valve  will  open  and  allow  steam  to  enter  the  low- 
pressure  heating  main. 

In  consequence,  the  vacuum  pump  will  automatically  start  into  opera- 
tion before  steam  is  admitted  into  the  low-pressure  heating  main.  The 
partial  vacuum  created  in  the  return 
mains  and  radiators  assures  quick  circula- 
tion as  soon  as  the  conserving  valve 
automatically  opens  and  permits  the 
steam  to  flow  into  the  main. 

When  steam  supply  is  cut  off  from 
the  heating  system  the  pump  will  continue 
to  operate  until  the  condensation  is  thor- 
oughly drained,  assuring  the  return  of  all 
of  the  condensation  to  the  boiler.  With 
the  types  of  boiler  used  with  heating 
systems  of  this  design,  this  is  a  very 
important  matter.  See  pages  173  to  176. 

Table  24-20.    Dimensions  of  Webster  Sylphon  Conserving  Valves        Fig.  24-73 
All  dimensions  in  inches  and  subject  to  slight  variation 

Size  AB  CE  F  GJ  K  R 


K'NO.    AND 
SIZE  OF  BOLT8 


4 

5 

6 

8 

10 


12 
12 
13 


15 


20 
20 

31  YA. 
31  y, 

••'•<> ,"., 


9 

10 
11 


9H 


16 


<<  A. 


MJ* 


8-H 

8-M 

»     :l.i 


17  Ji 


2^ 


28^ 


273 


The  Webster  Low-pressure  Boiler  Feeder — Series  16 

In  connection  with  heating  boilers  fed  from  hydro-pneumatic  tanks,  and 
under  certain  other  conditions,  a  Webster  Boiler  Feeder  is  useful.  This 
device  is  shown  on  Page  147,  as  part  of  a  Webster  Hydro-pneumatic  System. 


WATER  INLET 


EQUALIZING  PIPE 


Fig.  24-74.    Webster  Low-pressure  Boiler  Feeder 

When  the  water  level  in  the  boiler 
lowers,  the  ball  float  opens  the  feed 
valve  and  allows  the  water  to  discharge 
directly  to  boiler. 

The  valve  is  of  the  double-balanced 
type  with  large  orifice  area,  because  of 
the  low  differential  between  the  tank 
pressure  and  the  boiler  pressure.  The 
ball  float  is  large  enough  to  give  the 
lever  without  excessive  difference  of 
water  level. 

An  important  point  in  the  con- 
struction of  the  boiler  feeder  is  that 
the  valve  and  gear  are  within  the  cas- 
ing. There  are  no  outside  glands  to 
keep  tight  and  any  leakage  which  oc- 
curs is  within  the  body  of  the  device 
and  hence  into  the  boiler. 

The  working  parts  are  easily  ac- 
cessible, but  seldom  need  attention. 


EQUALIZING 
PIPE 


I 


Fig.  24-75.  Conventional 
arrangement  of  Webster 
Low-pressure  Boiler  Feeder 


SUPPORT  FOR  FEEDER 


power  required  to  move  the  valve 


Fig.  24-76 


Table  24-21.    Dimensions  of  Series  16  Webster  Low-pressure  Boiler  Feeder 
Dimensions  in  inches  and  subject  to  slight  variation 


Number      A 


B' 


G> 


116 


V* 
M 


216{     1> 
316{     f 


12  y2 


15 

15 

19 
19 


2  25^ 

2  25% 

2  25% 
2K 


14J4 


36^ 


1H 


2K 
2M 

3 
3 


UN 


15 
15 


10 
10 
10 
10 

12 
12 

12 
12 


15% 

15% 


21 
21 


274 


The  Webster  High-pressure  Sylphon  Trap 


Fig.  21-77.    The  Webster  High-pressure  Sylphon  Trap 

This  trap  is  in  many  respects  like  the  standard  Webster  Sylphon  Trap 
described  on  Page  242.  The  body  construction  is  the  same  except  that  the 
position  of  inlet  and  outlet  opening  and  the  union  connection  of  the  inlet 
are  reversed. 

As  the  trap  must  operate  at  comparatively  high  steam  pressure  with 
resulting  high  temperature,  the  thermostatic  member  or  bellows  is  located 
outboard  of  the  valve.  The  sylphon  bellows,  surrounded  in  this  position 
with  the  cooler  vapor  from  the  discharged  condensate  at  atmospheric  pres- 
sure, is  extremely  sensitive  to  the  much  higher  temperature  of  the  steam, 
and  consequently  acts  quickly  and  positively  to  close  the  valve  against  steam 
passage  through  the  trap. 

It  is  particularly  important  when  arranging  pipe  connections  that  the 
manufacturer's  directions  shall  be  specifically  followed. 

In  consequence  also  of  the  higher  pressure,  the  valve  piece  and  the  seat 
are  constructed  of  monel  metal,  which  successfully  resists  wire-drawing  and 
its  accompanying  wear. 

The  Webster  High-pressure  Sylphon  Trap  is  made  in  three  sizes  and 
for  two  pressure  ranges — Class  2  for  pressure  from  15  to  50  Ib.  per  sq.  in., 
and  Class  3  for  pressures  to  100  Ib.  per  sq.  in. 

Application  diagrams  for  this  device  are  shown  in  Chapters  18  and  20. 

Table  24-22.    Dimensions  of  Webster  High- 
pressure  Sylphon  Traps 





Fig.  2I-7K 


SIZE 

A 

B 

c 

D 

Yz"—  822 

3*A" 

W 

3J4" 

2J4" 

%  —833 

I,1,. 

2J/6 

2Ji 

3J^ 

1  —  8H 

4A 

2H 

3M 

•2~r, 


Fig.  24-79.     Webster  Hydro- 
pneumatic  Tank,  with 
Double  Control 


Webster  Hydro-pneumatic  Tanks 

Single  and  Double-control  Types 

Webster  Hydro-pneumatic  Tanks  are  used  in 
place  of  open-vent  tanks  for  receiving  returns  in 
steam  heating  systems  where  sufficient  head  room 
to  produce  the  necessary  static  head  is  not  available 

for  the  installation  of  a  plain 
receiving  tank. 

The  general  design  is 
the  same  as  that  of  Webster 
Steam-control  and  Webster 
Water  -  control  Receiving 
Tanks,  except  that  in  the 
Single-control  Hydro-pneu- 
matic Tanks  the  sink  pan 
and  rigging  control  the  es- 
cape of  air  through  the  vent 
pipe,  and  in  the  Double- 
control  type  this  feature  is 
supplemented  by  an  addi- 
tional sink  pan  rigged  to 
control  a  water  valve  in  the  discharge  piping. 

In  both  Single  and  Double-control  types  the  air  is  permitted  to  escape 
freely  until  the  tank  is  half  filled  with  condensation,  when  the  vent  closes 
and  the  remaining  air  is  confined.  The  air  vent  is  open  whenever  the  con- 
densation flows  by  gravity  against  the  resistance  in  the  outlet  connection. 
When  the  necessary  head  is  greater  than  that  due  to  the  tank  being  half 
full  of  condensation,  the  air  vent  is  closed.  Further  accumulation  of  air 
and  water  creates  additional  pressure  until  this,  added  to  the  gravity  head, 
overcomes  the  resistance  and  condensation  flows  through  the  outlet  until  the 
water  line  reaches  the  middle  of  tank.  Then  the  air  vent  opens  to  permit 
escape  of  air.  When  the  tank  has  no  gravity  head  to  heater  or  boiler  the  neces- 
sary head  to  overcome  resistance  in  the  outlet  is  by  confined  pressure  only. 
The  Double-control  Hydro-pneumatic  Tank,  in  addition,  has  its  water- 
control  valve  arranged  to  close  just  before  the  water  level  reaches  the  bottom 
of  the  tank.  The  Double-control  type  serves  to  prevent  admission  of  air  into 
the  system,  through  discharge  from  the  tank,  when  the  pressure  in  the  open 
feed-water  heater  or  boiler  may  be  less  than  that  of  the  atmosphere. 

Both  Single  and  Double-control  Tanks  are  used  under  pressure  greater 
than  the  atmosphere  and  in  most  instances  must  be  provided  with  means  for 
preventing  excessive  pressure  due  to  obstruction  of  overflow.  For  this  pur- 
pose a  water-relief  valve  is  provided,  which  should  be  piped  to  an  open  funnel 
to  facilitate  observation  and  correction  of  unnecessary  waste. 

Both  Single  and  Double-control  types  of  tanks  are  made  of  riveted 
flange  steel  plate,  have  flat  heads  and  are  for  installation  in  horizontal 
position.  A  water-trough  running  along  the  top  distributes  the  water  and 
assures  that  sink  pans  are  kept  filled  with  water. 

276 


Manholes  and  covers  and  gauge  glass  fittings  are  regular  equipment 
with  both  types  of  tanks.   Sizes  listed  are  standard.    Others  made  to  order. 

Table  24-23.     Dimensions  of  Webster  Hydro-pneumatic  Tanks 
Openings  will  be  bushed  to  suit  requirements.     All  dimensions  in  inches 

Single-control   Type 


nhole 


Size 


Inlet        Outlet     Vent  valve    Overflow 


18  x  48 

4 

4 

*4            4 

29H 

30^ 

10 

12 

24^ 

14 

18 

24x72 

5 

5 

\\4           5 

43?4 

42^ 

13 

18 

36  J^ 

18 

22% 

36  x  96 

(2)8 

8 

l/"^            6 

58 

545i 

18 

18 

48?/8 

24 

2V/t 

Double-control  Type 


Size 


Inlet    Outlet    Vent  valve    Overflow     A 


18  x  18  I 
2 1  x  72  5 
:\i>  x  (<6  (2)8 


4 

5  433i 

6  58 


30}^  10  12 
42^  13  18 
18  18 


14 

36J4      18 
1J!:!  s      24 


18 

22^ 
28K 


20 

22        25 Ji 
35 


For  ratings,  see  Table  13-1,  page  138. 
277 


Webster  Expansion  Joints 

Webster  Expansion  Joints  are  constructed  with  cast-iron  bodies  and 
brass-slip  sleeves  and  in  both  single  and  double-slip  types. 

The  body  of  the  Webster  Expansion  Joint  is  provided  with  anchors 
made  integral  with  the  body  castings  for  rigid  connection  to  a  foundation  or  a 
bracket.  Service  connections  are  provided  for  greatest  convenience  in 
tapping  the  steam  main  for  branch  piping.  Drip  outlets  also  are  provided. 


Fig.  21-82.    Class  D  (at  left) 
Webster  Expansion  Joint 


Fig.  24-83.     Class  DH  (at  right) 
Webster  Expansion  Joint 


Fig.  21-81.     Class  G  (at  left) 
Webster  Expansion  Joint 


Fig.  21-85.     Class  GH  (at  right) 
Webster  Expansion  Joint 


278 


B' 


M=SIZE  OF  SERVICE 
CONNECTIO 


Fig.  24-86 


Table  24-24.     Class  D  Webster  Expansion  Joints  for  Low-Pressure  Steam 

Dimensions  (in  inches) 


Size 


B' 


F' 


K 


2 

3 

Wi 
4 
5 
6 

7 

8 
10 
12 

14 
16 
18 

20 


<>X 
6 


18 
18 


4% 


3 
3 
3 
3 


3 
3 
3 
3 


16  4  4 

16  5  5 

17H       5  5 

6  6 


9 
10 
11 


20% 


25  Ji 


9X 


2&yg  s 

261A  8 

9X       2SX  8 

9X       30Ji  8 


6 
8 
8 
8 

8 

8 

12 

12 


16 
19 

21 

2VA 
25 


2Vg 

4 
5 

9X 
12 


» 


10 
11 
12 


1»/4 
lj| 

m 

2 


2-  Ji 

2-  3X 
2-  Ji 

4-  Ji 

4-  % 

4-  M 

4-  Ji 

4-  Ji 
4-  Ji 
4-1 
4-1 

4-1  ys 


4-1H 

4-1 H 


Maximum  working  pressure,  15  Ib.  per  sq.  in. 

This  joint  has  single  slip  and  maximum  traverse  of  5  in.  and  is  made 
with  a  close-grained  cast-iron  body  and  brass  tubing  or  cast-brass  sleeve. 

Standard  equipment  includes  service  and  drip  connections,  anchor  plates 
and  gland  packing. 

Companion  flanges  are  furnished  only  when  specially  ordered. 

Flanges  are  drilled  low-pressure  standard  unless  specially  ordered 
otherwise. 

279 


Table  24-25.     Class  DH  Webster  Expansion  Joints  for  High-Pressure  Steam 

Dimensions  (in  inches) 


Size 


4 

5 

6 

7 

8 

10 

12 


(>H 
6 

6*A 


13^8 


16 
16 


22^ 


3 
3 
3 
3 

4 
5 
5 
6 
6 
6 
6 
7 


3 
3 

3 
3 

4 
5 
5 

6 
6 

8 
8 
8 


a 
6 

7 


9 
10 
11 


16 
19 


11 
13 
12 


17M 

21  % 

24% 


zy* 

4 
5  2 


2-  J^ 
2-  ^ 
2-  ^ 
2-  ?4 

4-  y, 

4-  Jl 
4-  Jl 
4-  Jl 
4-  Jl 

4-  y( 

4-1 
4-1 


Maximum  working  pressure,  125  Ib.  per  sq.  in. 

This  joint  has  single  slip  and  maximum  traverse  of  5  in.  and  is  made 
with  a  close-grained  cast-iron  body  and  brass  tubing  or  cast-brass  sleeve. 

Standard  equipment  includes  service  and  drip  connections,  anchor 
plates,  limit  bolts  and  gland  packing. 

Companion  flanges  are  furnished  only  when  specially  ordered. 

Flanges  are  drilled  low-pressure  standard  unless  specially  ordered 
otherwise. 


280 


K    -NO.  AND  SIZE  OF  CORES       M  =  8IZE  OF  SERVICE 
CONNECTION 


Fig.  24-88 


Table  24-26.    Class  G  Webster  Expansion  Joints  for  Low-Pressure  Steam 

Dimensions  (in  inches) 


Size 


D' 


F' 


M 


22  H 


5 

6 

7 

8 

10 

12 

14 

16 

18 

20 


ulA 

17 

18  j| 


27% 


31% 

33^ 


20^ 
22 


44 


3 
3 
3 
3 
4 
5 
5 
6 
6 
8 
8 
8 
8 
8 
12 
12 


9 

10 
11 


16 
19 
21 

23Y2 
25 


2% 


12 
13 
H 


2tt 
3 


13^ 


13* 
1% 

2 


1% 
2 


2-  % 
2—  % 
2-  % 
2-  % 
4-  J^ 
4-  K 
4-  /4 
4-  J^ 
4-  % 
4-  Ji 
4-1 
4-1 

4-1  ys 


4-1  ^ 


Maximum  working  pressure,  15  Ib.  per  sq.  in. 

This  joint  has  double-slip  and  maximum  traverse  of  10  in.  and  is  made 
with  a  close-grained  cast-iron  body  and  brass  tubing  or  cast-brass  sleeve. 

Standard  equipment  includes  service  and  drip  connections,  anchor 
plates  and  gland  packing. 

Companion  flanges  are  furnished  only  when  specially  ordered. 

Manges  are  drilled  low-pressure  standard  unless  ordered  otherwise. 


281 


inte  i  JBIMK 


E1- 


d 


V 

~-\. I a 


hi 'A  DRIP 


I  ~" 

-  J2- 

-4-!i-jk- 

t 

D' 

sfe 

T 

IL1 


K  =  NO.  AND   SIZE  OF  CORES  M  =SIZE  OF  SERVICE 

CONNECTION 


Fig.  24-89 


Table  24-27.     Class  GH  Webster  Expansion  Joints  for  High-Pressure  Steam 

Dimensions  (in  inches) 


Size 

B 

B< 

c 

D 

D. 

E 

E. 

F 

F' 

J- 

P 

K1 

M 

l*A 

16  & 

8& 

22^ 

8 

3 

5 

8% 

2*4 

«j 

1% 

1% 

2-  % 

1 

2 

16*A 

8j/g 

22*A 

3 

3 

6 

8% 

2*4 

31 

1% 

1% 

2-  % 

i*A 

2*4 

16*A 

8*4 

23*A 

3 

3 

7 

1Q/4 

3*4 

3/4 

1% 

1% 

2-  3A 

2 

3 

18*4 

9*4 

25*A 

3 

3 

7/4 

11 

3*4 

1% 

1% 

2-  % 

2 

3/4 

18 

9 

25*A 

4 

4 

9 

13 

3*4 

3% 

2 

2 

4-  % 

2 

4 

19 

9*A 

26% 

5 

5 

9 

12 

4*4 

2*A 

2*A 

4-  % 

2*A 

5 

19*A 

93A 

27*A 

5 

5 

10 

14*4 

4*4 

2*A 

2*A 

4-  % 

2*/2 

6 

19*4 

97A 

27% 

6 

6 

11 

15J4 

5 

53^ 

3 

3 

4-  14 

2*A 

8 

23 

n*A 

6 

8 

13/4 

18*A 

6% 

7*4 

5 

3 

4-  K 

3*A 

10 

24*4 

12*A 

33H 

6 

8 

16 

21% 

8 

5 

3 

4-1 

4 

12 

25% 

12% 

36*A 

7 

8 

19 

9 

m 

5 

3*A 

4-1 

5 

Maximum  working  pressure,  125  Ib.  per  sq.  in. 

This  joint  has  double-slip  and  maximum  traverse  of  10  in.  and  is  made 
with  a  close-grained  cast-iron  body  and  brass  tubing  or  cast-brass  sleeve. 

Standard  equipment  includes  service  and  drip  connections,  anchor 
plates,  limit  bolts,  and  gland  packing. 

Companion  flanges  are  furnished  only  when  specially  ordered. 

Flanges  are  drilled  low-pressure  standard  unless  specially  ordered 
otherwise. 

282 


Table  24-28.     Distance  Between  Anchor  Points  and  Webster  Expansion  Joints 
for  Various  Steam  Pressure  Conditions 

The  following  table  is  recommended  as  a  guide  in  the  design  of  steam  piping  for  determination  of 
the  proper  points  of  installation  of  Webster  Expansion  Joints.  In  such  design  the  maximum  pressure  which 
the  pipe  line  must  sustain  during  acceptance  tests  or  other  special  conditions  must  be  selected  as  the  "  Gauge 
pressure" 


Gauge 
pressure 

Temperature 
difference 
above  zero 

Expansion 
Inches 
per  100  feet 

Safe  maximum  distance  in 
feet  between  anchors 
for  single-slip 
expansion  joints* 

0 

212 

1.53 

260 

5.3 

227 

1.64 

245 

10.3 

240 

1.73 

225 

15.3 

250 

1.80 

220 

20.3 

259 

1.87 

215 

25.3 

267 

1.93 

210 

30.3 

274 

1.98 

202 

40.3 

286 

2.06 

195 

50.3 

297 

2.14 

190 

75.3 

320 

2.31 

175 

100.3 

337 

2.43 

166 

125.3 

352 

2.54 

160 

'For  double-slip  joints,  the  safe  distance  from  the  joint  to  an  anchor  in  each  direction  may  be  the  distance 
speciGed  for  a  single  joint,  provided  the  body  of  the  double  joint  itself  is  securely  anchored 

Webster  Series  21  Steam  Separators 

For  working  pressures  up  to  200  Ib.  per  sq.  in. 

Webster  Steam  Separators  of 
the  standard  types  for  removing 
moisture  from  live  steam,  have 
cast-iron  corrugated  baffles  against 
which  the  steam  impinges,  causing 
a  sudden  change  in  direction  of 
flow  and  consequently  freeing  the 
steam  of  the  entrained  moisture. 

The  port  openings  in  every 
Webster  Steam  Separator  are  of 
such  size  as  to  minimize  loss  of 
steam  pressure  from  unnecessary 
friction. 

These  separators  may  also  be 
j   e  •  i 

used  tor  special  purposes,  as  re- 
moving moisture  from  compressed 
air,  assuring  operation  of  steam 
whistles  by  removing  moisture 
from  their  steam  supplies,  etc. 

The  material  ordinarily  used 
in  the  shells  is  close-grained  cast- 
iron,  but  special  shells  of  semi- 
steel,  cast  steel  or  other  material 
can  be  furnished. 

Gauge-glass  fittings  and  drain 
valves  are  usual  equipment  but 
are  furnished  only  as  extras  when 
ordered. 

283 


Fig.  21-90.     Vertical  typ< 


Fig.  24-91.     Horizontal  type 


Table  24-29.    Dimensions  of  Webster  Series  21  Steam  Separators 
All  dimensions  in  inches 

Companion  flanges  and  gauge  and  drain   fittings  furnished  only  when  specially  ordered.     Flanges 
are  drilled  to  high-pressure  standard  unless  otherwise  ordered 


Fig.  24-92.     Vertical  Type 
Down-flow  only 


Size 


Dimensions 


Drip 


Flanges 


Outside 
diameter 


Bolt 
circle 


No.  &  sizes 
of  bolts 


4 

5 
6 
8 

10 
12 


8% 

9 
10 
11 


7% 
7Ji 
9% 


15 


20  }4 


13 

15% 
17% 


4-  % 

4-  % 

8-  % 

8-  % 

8-  % 

8-  % 

12-  % 

12-  H 

16-1 


Fig.  24-93.    Horizontal  Type 


HI 


Dimensions 

Flanges 

Size 

B 

F 

G 

H 

Drip 

Outside 

diameter 

Bolt 
circle 

No.  &  sizes 
of  bolts 

2 

9J-S 

3>i 

12M 

8^ 

« 

6^ 

5 

4-  ys 

3 

11^ 

5% 

14% 

IOM 

% 

8% 

6^ 

8-  % 

4 

13'  s 

5% 

16 

11H 

1 

10 

7>g 

8-  % 

5 

14J^ 

7% 

17% 

14^ 

1 

11 

9% 

8-  % 

6 

16^ 

8H 

19H 

16 

1 

12« 

10H 

12-  % 

8 

20% 

ION 

23% 

20J4 

1 

15 

13 

12-  yg 

10 

24?x8 

12Ji 

26% 

24H 

1% 

17H 

15% 

16-1 

12 

27^ 

14% 

30 

29% 

1M 

20^ 

17% 

16-1YS 

284 


Special  Types  of  Webster  Steam  Separators 
Working  pressures  up  to  150  Ib.  per  sq.  in. 


Fig  21-91 

Class  L — Angle  Type 
with  horizontal  outlet 


Fig.  24-95 

Class  M— Angle  Type 
with  bottom  outlet 


Fig.  24-96 

Class  N— Angle  Type 
YI  ith  top  outlet 


Table  24-30.     Ratings  of  Webster  Steam  Separators 
Pounds  per  minute  at  average  gauge  pressures.    Based  upon  a  pipe  velocity  of  6000  ft.  per  min. 


Gauge  pressures 

Size  of                             100  Lb. 

125  Lb. 

150  Lb. 

200  Lb. 

separator                              per 

per 

per 

per 

in.                             sq.  inch 

sq.  inch 

sq.  inch 

sq.  inch 

2                           35. 

43.3 

51.6 

66.6 

3                           78.3 

96.7 

112. 

141. 

4                         140. 

167. 

196. 

250. 

5                         215. 

258. 

300. 

391. 

6                         317. 

383. 

450. 

583. 

7                         433. 

516. 

600. 

783. 

8                         .r).->0. 

660. 

800. 

1000. 

10                           883. 

1083. 

1250. 

1580. 

12                       1250. 

1533. 

1800. 

2333. 

285 


CHAPTER  XXV 

Specifications  for  Webster  Systems 

THE  following  specifications  cover  typical  Webster  Systems  only  in  a 
general  way,  and  are  subject  to  many  variations.    It  is  advised  that 
wherever  practical  a  Webster  Service  Engineer  be  called  into  con- 
sultation during  the  preparation  of  plans  and  specifications  for  Webster 
Systems. 

Specifications  for  the  Webster  Vacuum  System  of 
Steam  Heating 

(This  specification  is  written  for  a  system  of  the  usual  up-feed  type. 
For  the  variations  known  as  the  Webster  Conserving  System  and  the  Webster 
Hylo  System,  revised  special  clauses  will  be  furnished  by  Warren  Webster 
&  Company  on  application.) 

GENERAL:  (Here  specify  the  general  requirements  of  ihe  contract,  such  as  intent  of 
drawings  and  specifications;  verification  of  measurements;  co-operation  with  other  con- 
tractors ;  foreman ;  ordinances ;  permits ;  protection  of  work  and  buildings ;  rights  reserved ; 
extra  work;  return  of  specifications  and  drawings;  payments,  etc.) 

CUTTING  OF  FLOORS  AND  WALLS  :  The  [building]  [heating]  contractor  will  cut  all  holes 
in  floors  and  walls  and  provide  trenches  and  covers  for  piping  which  may  be  necessary  for 
this  work,  and  at  completion  make  all  repairs  to  floors  and  walls  so  cut. 

SCOPE  OF  WORK  :  This  specification  is  intended  to  cover  a  2-pipe  low-pressure  heating 
system  known  as  the  Webster  Vacuum  System  of  Steam  Heating. 

It  is  intended  to  supply  radiation  for  heating  the  building  to  a  temperature  of  .... 

degrees  fahr.  when  the  outside  temperature  is or  a  corresponding  equivalent  difference 

in  temperature,  with  doors  and  windows  reasonably  tight. 

SPECIAL  APPARATUS:  'The  basis  of  this  specification  being  a  Webster  System,  each 
bidder  is  required  to  submit  his  proposal  for  furnishing  apparatus  manufactured  by  Warren 
Webster  and  Company. 

*ALTERNATE  PROPOSALS  will  be  considered  for  the  use  of  modulation  supply  valves  and 

thermostatic  return  traps  of  the  same  supply  and  return  tappings  and  as  made  by 

,  provided  each  bidder  states  in  his  proposal  the  sum  which  will  be  added  to 

or  deducted  from  his  main  bid  in  case  they  are  used. 

STANDARD  APPARATUS:  In  addition  to  the  special  apparatus,  this  contractor  is  to  fur- 
nish all  other  material  and  labor  necessary  for  the  complete  work  as  shown  on  plans  or  called 
for  in  specifications. 

RADIATION:  All  pipe  coils  must  be  made  up  of  full-weight  [mild-steel]  [genuine 
wrought  iron]  pipe  and  best  gray-cast  iron  fittings  and  manifolds.  All  radiators  must  be  of 

the pattern  equal  in  every  respect  to  that  manufactured  by  

and  must  be  of  the  heights  and  columns  shown  on  plans.    They  must  be  of  the  [steam]  [hot- 
water]  type. 

(Note:  If  of  hot-water  pattern,  specify  that  the  radiators  "shall  be  connected  with  the 
supply  at  the  top  and  the  return  at  the  diagonally  opposite  lower  corner."  If  of  steam 
type,  specify  that  they  "shall  be  provided  with  eccentric  bushings  and  connected  so  that 
the  bottom  of  the  return  connection  will  be  lower  than  the  bottom  of  the  supply  connection." 
Where  Webster  Modulation  Valves  are  to  be  used,  hot-water  type  radiators  should  be 
specified.) 

*  To  he  inserted  in  case  the  Architect  or  Engineer  desires  to  obtain,  for  comparative  purposes,  an  alternate  price  upon  ap- 
paratus of  a  make  other  than  Webster 

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Contractors  supplying  radiation  ordered  for  this  work  shall,  if  they  be  called  upon 
to  do  so,  demonstrate  to  the  satisfaction  of  the  owners  or  their  authorized  representative, 
that  the  radiation  furnished  contains  in  each  section  of  the  different  types  supplied  the 
amount  of  prime  heating  surface  mentioned  in  the  lists  published  by  the  manufacturers  of 
I  lie  respective  types.  This  must  be  demonstrated  by  actual  measurement  and  the  develop- 
ment of  the  exposed  surface  of  the  sections. 

The  heating  contractor  is  to  instruct  the  manufacturer  of  the  radiation  that  he  requires 
same  to  be  thoroughly  pickled  and  cleaned  before  shipment  and  that  the  outlets  are  to  be 
plugged  with  loose  wooden  plugs.  The  manufacturer  must  issue  his  certificate  to  the  con- 
tractor showing  that  these  radiators  have  been  so  cleaned.  These  radiators  are  to  be  kept 
plugged  until  same  are  connected  to  the  different  pipe  lines. 

Air-valve  tappings  are  to  be  plugged. 

Radiators  must  be  tapped  or  bushed  for  sizes  of  supplies  and  returns  as  shown  on  plans. 

COIL  HANGERS:  Overhead  radiators  are  to  be  hung  in  special  pipe  hangers  and  in  no 
case  shall  these  coil  hangers  be  more  than  10  ft.  apart. 

Wall  coils  are  to  have  spring  pieces  and  are  to  be  hung  on  cast  or  wrought-iron  plates 
spaced  as  directed  by  their  manufacturer,  screwed  to  IJ^-in.  strap-iron  brackets  bent  to 
shape,  and  securely  fastened  to  the  walls  with  two  expansion  bolts  each.  Brackets  must  be 
spaced  not  over  10-ft.  centers.  Wall  radiators  must  be  hung  as  directed  by  manufacturers. 

Straps  shall  be  painted  two  coats  of  lead  and  oil  paint  of  colors  as  directed  by  owners 
before  radiators  are  set  in  place.  Owners  must  be  given  opportunity  to  paint  walls  or  ceil- 
ings before  radiators  are  set. 

RETURN  TRAPS:  The  return  end  of  every  radiator,  pipe  coil  or  other  form  of  heating 
unit  must  be  provided  with  a  Webster  Return  Trap  (of  the  type  selected).  The  size  of  the 
trap  shall  be  governed  by  the  amount  of  condensation  from  the  radiation  unit  as  called  for 
on  plans.  The  connections  of  Webster  Return  Traps  must  be  made  to  the  approval  of 
Warren  Webster  &  Company,  who  will  provide  the  contractor  with  service  details  showing 
approved  forms  of  connection. 

SUPPLY  VALVES:  Each  radiation  unit  must  be  provided  with  a  Webster  Modulation 
Valve  connected  to  the  top  supply  tapping. 

The  sizes  of  supply  valves,  the  radiator  tappings  and  the  sizes  of  horizontal  branches 
from  risers  to  radiators  must  be  as  shown  on  the  plans,  or  as  hereafter  described  in  this 
specification. 

PIPE:  All  low-pressure  pipe  must  be  full-weight  [mild-steel]  [genuine  wrought-iron] 

equal  to  that  manufactured  by All  screwed  piping  must  be  fitted 

with  occasional  flanged  unions.  Where  supply  pipes  are  reduced  in  the  run,  eccentric 
reducing  couplings  must  be  used. 

Straighten  all  pipe,  ream  all  burrs  and  remove  all  dirt  before  erecting  pipe  or  fittings. 
Have  all  runs  plumb  and  parallel  with  building.  Provide  Webster  Expansion  Joints  of  the 
types  and  sizes  and  at  the  points  shown  on  plans.  Support  all  pipes  securely  and  in  such 
manner  as  to  permit  unobstructed  movement  between  anchorages  for  expansion  and 
contraction. 

So  far  as  possible,  all  horizontal  runs  must  be  graded  in  the  direction  of  steam  flow. 

FITTINGS:  All  fittings  shall  be  best  gray-iron,  straight  and  true  and  free  from  blow- 
holes or  other  defects;  equal  to  those  manufactured  by Fittings  for  low  pres- 
sure shall  be  standard  weight;  those  for  high  pressure  shall  be  extra  heavy. 

VALVES:   All  check,  gate  and  globe  valves  must  be  equal  to  those  manufactured  by 


HEAT  MAINS:  From  the  low -pressure  side  of  pressure-reducing  valve  run  a  pipe  to 
connect  into  the  exhaust  steam  main  where  shown  on  plans.  (Here  should  follow  a  descrip- 
tion of  the  course  of  the  steam  main  and  its  branches.) 

Horizontal  runs  must  grade  not  less  than  1  in.  in  25  ft. 

LIVE  STEAM  CONNECTION:  Connect  a  .  .  .-in.  line  from  outlet  in  live  steam  main 
(where  indicated  on  plans)  to  the  heating  main  through  the  pressure-regulating  valve. 

This  valve  shall  be  .  .  .-in.  size  and  equal  to  that  manufactured  by ,  and 

shall  be  set  to  reduce  the  steam  pressure  from  ...  to  (1  Ib.  per  sq.  in.  or  less). 

Provide  a  3-valve  bypass  as  shown,  the  valve  in  front  of  the  reducing  valve  to  be 

287 


of  the  globe  pattern.  Run  a  "control  pipe"  as  shown.  Place  a  low-pressure  gauge  and  a 
j^-in.  pop  alarm  valve  set  at  10-Ib.  pressure  in  the  heat  main  about  10  ft.  from  the 
discharge  of  pressure-reducing  valve. 

RISERS:  A  system  of  supply  and  return  risers  is  to  be  run  as  shown  on  plans.  Risers 
are  to  be  run  [exposed]  [concealed]  and  are  to  be  of  sizes  marked  on  plans.  All  radiator 
branches  must  grade  back  to  risers  or  mains  with  as  much  grade  as  possible,  in  no  case 
less  than  1  in.  in  5  ft.  All  connections  are  to  be  made  with  ample  provision  for  expansion 
and  contraction  and  particular  care  is  to  be  taken  that  branches  are  run  without  pockets. 

RETURN  PIPING:  All  return  risers  and  branches  are  to  connect  into  return  mains. 
Horizontal  return  piping  must  be  graded  toward  the  vacuum  pump  not  less  than  1  in. 
in  40  ft. 

DIRT  TRAPS:  The  bottom  of  all  supply  connections  taken  from  the  heating  main  must 
be  dripped  into  the  vacuum  return  by  means  of  a  cooling  leg,  a  gate  valve,  a  Webster 
Dirt  Strainer  and  a  Webster  Return  Trap  of  size  shown  on  plans. 

Note  :  In  large  installations  it  is  advisable  to  run  a  separate  gravity  drip  line  and  connect  drip  of 
each  riser  or  drip  point  of  main  through  %-in.  line  with  gate  valve  to  this  line.  The  discharge  of  this 
gravity  drip  line  to  be  to  the  feed- water  heater  through  loop  seal  or  to  the  vacuum  return  through  Webster 
Heavy-duty  Trap. 

DIRT  STRAINERS:  Provide  and  connect  Webster  Dirt  Strainers  of  the  sizes  specified 
and  at  the  points  indicated  on  the  plans. 

LIFT  FITTINGS:  Where  lifts  occur  in  the  vacuum  return  lines  they  are  each  to  be  pro- 
vided with  a  pair  of  Webster  Lift  Fittings  of  the  sizes  called  for  on  plans  and  connected 
according  to  special  service  detail  furnished  by  the  manufacturer. 

BOILERS:  (Here  specify  the  make,  size  and  type  of  boiler  or  boilers  required;  also  the 
equipment  required  for  the  complete  boiler  plant,  including  smoke  breeching,  damper 
regulator,  gauges,  feed  pump,  injector  and  any  other  necessary  accessories.) 

VACUUM  PUMPS:  (Here  specify  the  make,  size,  type  and  number  of  pumps  required 
"to  be  furnished  upon  (concrete  or  other  material)  foundations  to  be  provided  by  this 
contractor."  Detail  specifications  of  pumps  should  describe  either  the  electric-driven  type 
(Nash,  etc.)  or  the  steam-driven  type  (Blake-Knowles,  Burnham,  Marsh,  etc.).  For  steam- 
driven  pump,  specify  "simplex,  double-acting  type,  brass  lining,  and  fitted  for  hot-water 
service"  and  that  "each  pump  shall  be  provided  with  a  forced-feed  lubricator  of  approved 
make  and  having  a  capacity  of  one  quart." 

Each  pump  shall  have  ample  capacity  for  handling  the  products  of  condensation  from 
the  entire  heating  system. 

The  discharge  from  steam-driven  vacuum  pump  must  be  connected  to  the  proper 
tapping  in  the  receiving  tank.  If  discharge  outlet  is  located  on  the  side  of  the  steam 
pump,  tap  the  cover  plate  above  the  discharge  valves  and  run  54 -in.  air  line,  connecting 
to  discharge  pipe. 

All  connections  must  be  properly  valved  and  made  complete. 

SUCTION  STRAINER  :  In  the  suction  pipe  to  the  vacuum  pump,  place  a  Webster  Suction 
Strainer.  This  strainer  must  be  connected  to  accord  with  special  service  detail  furnished 
by  the  manufacturer. 

VACUUM  GOVERNOR:  In  the  steam  connection  to  vacuum  pump  below  the  lubricator 
there  must  be  placed  a  ...  -in.  Webster  Vacuum-pump  Governor  with  3-valve  bypass. 
Same  must  be  connected  by  means  of  J^-in.  vacuum  line  to  the  suction  strainer  and  also 
to  the  vacuum  gauge  on  board.  Each  branch  must  be  provided  with  a  globe  valve. 

GAUGES:  Furnish  and  erect  at  convenient  position  two  5^-in.  compound  gauges 
mounted  on  a  slate  board.  Connect  one  gauge  to  equalizing  line  between  heat  main  and 
reducing  valve,  one  gauge  to  a  line  connecting  vacuum  governor  with  vacuum  return  at 
suction  strainer.  All  gauge  piping  to  be  J^-in.  and  all  branches  valved. 

AIR-SEPARATING  TANK:  Furnish  a  Webster  Air-separating  Tank  ...  in.  in  diameter 
by  ...  in.  long.  This  tank  is  to  be  of  the type. 

Erect  the  separating  tank  as  high  above  the  heater  as  possible,  as  shown  on  plans, 
and  to  it  make  connections  from  discharge  of  vacuum  pumps  and  to  feed-water  heater 
through  long  loop  seal. 

From  top  outlet  on  tank  make  a  vent  connection  to  atmosphere. 

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FEED-WATER  HEATER:  Furnish  and  erect  on  foundation  one  Webster  Feed-water 
Heater  of  sufficient  capacity  for  heating  the  required  feed  water  to  within  5  deg.  of  the  tem- 
perature of  the  steam  entering  same. 

The  drip  from  oil  separator  is  to  connect  to  waste  line  through  a  Webster  Grease  Trap 
with  3-valve  bypass  and  check  valve  as  shown  in  special  service  detail. 

The  contractor  is  to  make  all  necessary  steam,  water  and  drain  connections  as  shown 
or  called  for. 

STEAM  SEPARATOR  :  Furnish  and  connect  Webster  Steam  Separators  of  approved  type 
to  steam  lines  as  shown  or  called  for. 

The  drip  from  bottom  of  each  separator  is  to  be  connected  into  a  high-pressure  trap 
of  approved  make.  Each  trap  is  to  be  provided  with  a  3-valve  bypass.  The  discharge 
lines  from  these  traps  are  to  be  connected  into  the  feed-water  heater. 

COVERING  :  After  all  piping  and  apparatus  have  been  tested  and  made  tight  to  the 
approval  of  the  [architect]  [engineer]  or  his  representative,  the  following  covering  is  to  be 
applied.  (Here  specify  necessary  covering  for  boilers,  heater,  separator,  and  all  [specify 
which]  piping,  valves  and  fittings.) 

PAINTING  AND  BRONZING:  All  radiators,  coils  and  exposed  piping  throughout  the  build- 
ing, after  being  tested,  are  to  be  painted  or  bronzed  as  follows: 

All  radiators,  coil  and  exposed  piping  are  to  be  painted  one  coat  of  sizing  and  then 
[bronzed]  [painted]  [two]  coats;  color  as  selected  by  architect  or  owner. 

All  exposed  parts  of  boiler  and  heater  to  be  painted  two  coats  of  black  asphaltum  paint. 

TESTS:  All  concealed  pipes  and  risers  shall  be  tested  and  made  tight  under  an 
hydraulic  pressure  of  50  Ib.  per  sq.  in.  before  being  covered  in.  The  entire  system  shall 
be  tested  and  made  tight  under  10-lb.  steam  pressure. 

Thoroughly  blow  out  the  pipes  to  free  them  from  all  accumulation  of  dirt,  chips  and 
other  material,  making  temporary  piping  connections  for  this  purpose. 

FUEL  AND  LABOR  :  The  heating  contractor  will  furnish  all  fuel  and  labor  required  for 
testing  and  adjusting  boilers  and  apparatus  and  for  drying  out  covering  on  boilers  (and 
smoke  breeching) .  He  will  also  remove  water  and  ashes  resulting  therefrom. 

TEMPORARY  SETTING  OF  RADIATORS:  Upon  written  request  of  the  [architect]  [engineer] 
the  contractor  shall  connect  up  for  temporary  heat  such  radiators  as  shall  be  designated. 
These  radiators  shall  afterwards  be  disconnected,  moved,  cleaned,  and  afterwards  recon- 
nected permanently.  Wall  radiators  and  radiators  without  leg  sections  shall  be  supported 
on  wooden  blocks.  Each  radiator  is  to  have  two  pipe  connections  and  no  supply  or  return 
valves  are  to  be  attached  at  this  time.  Each  bidder  will  state  in  his  proposal  a  unit  price 
which  he  will  charge  for  making  temporary  connections  as  described  above. 

INSPECTION  :  This  job  is  to  be  inspected  by  a  representative  of  the  manufacturer  of  the 
return  traps  before  acceptance  and  he  shall  submit  a  written  report  of  the  same  to  the  Archi- 
tects. 

GUARANTEE  :  The  contractor  must  agree  to  make  good  at  his  own  expense  any  defects 
in  labor  or  material  furnished  by  him  for  this  work  which  may  develop  within  one  year 
from  the  completion  of  this  contract,  reasonable  wear  and  tear  excepted. 

The  entire  system  wheta  completed  is  to  be  tested  in  the  presence  of  the  [architect] 
[engineer]  or  his  representative,  and  made  tight  without  caulking.  The  contractor  will  be 
held  liable  for  any  damage  to  the  building  or  its  contents  due  to  leaks  or  other  defects  in  his 
work  which  may  develop  during  the  period  of  installation  and  test. 

Specifications  for  the  Webster  Modulation  System  of 

Steam  Heating 

(This  specification  is  written  for  a  large  residence.  It  is,  of  course, 
subject  to  modifications  and  variations  for  other  kinds  of  buildings,  for  other 
sources  of  steam  than  house  boiler,  etc.,  for  which  revised  typical  specifica- 
tion clauses  will  be  furnished  by  Warren  Webster  &  Company  on  request.) 

GENERAL:  (Here  specify  the  general  requirements  of  the  contract  such  as  intent  of 
drawings  and  specifications;  verification  of  measurements;  co-operation  with  other  con- 

289 


tractors;  foreman;  ordinances;  permits;  protection  of  work  and  buildings ;  rights  reserved ; 
extra  work;  return  of  specifications  and  drawings;  payments,  etc.) 

CUTTING  OF  FLOORS  AND  WALLS:  The  [building]  [heating]  contractor  will  cut  all  holes 
in  floors  and  walls  and  provide  trenches  and  covers  for  piping  which  may  be  necessary  for 
this  work,  and  at  completion  make  all  repairs  to  floors  and  walls  so  cut. 

SCOPE  OF  WORK:  This  specification  is  intended  to  cover  a  2-pipe  open-return  heating 
system  known  as  the  Webster  Modulation  System  of  Steam  Heating. 

It  is  intended  that  sufficient  radiation  shall  be  supplied  for  heating  the  building  to  a 
temperature  of  ...  deg.  fahr.  when  the  outside  temperature  is  ...  deg.  fahr.  or  a 
corresponding  equivalent  difference  in  temperature,  based  upon  all  doors  and  windows 
being  fitted  reasonably  tight  to  prevent  excessive  infiltration  of  cold  air. 

SPECIAL  APPARATUS:  The  basis  of  this  specification  being  a  Webster  System,  each 
bidder  is  required  to  submit  his  proposal  for  furnishing  apparatus  manufactured  by  Warren 
Webster  and  Company. 

*ALTEHNATE  PROPOSALS  will  be  considered  for  the  use  of  modulation  supply  valves 
and  thermostatic  return  traps  of  the  same  supply  and  return  tappings  and  as  made  by 

,  provided  each  bidder  states  in  his  proposal  the  sum  which  will  be  added  to 

or  deducted  from  his  main  bid  in  case  they  are  used. 

STANDARD  APPARATUS:  In  addition  to  the  special  apparatus,  this  contractor  is  to  fur- 
nish all  other  material  and  labor  necessary  for  the  complete  work  as  shown  on  plans  or  called 
for  in  specifications. 

BOILERS:  (Here  specify  the  make,  size  and  type  of  boiler  or  boilers  required,  specifying 
also  the  equipment  required  for  the  complete  boiler  plants,  including  smoke  breeching  and 
other  necessary  accessories.)  (Indicate  what  contractor  is  to  build  boiler  foundation.) 

Note:  Boilers  and  auxiliary  equipment  must  be  installed  in  accordance  with  Warren  Webster  & 
Company's  standard  service  details. 

DAMPER  REGULATOR:  Furnish  one  Webster  Damper  Regulator  for  each  boiler;  to  be 
connected  in  accordance  with  the  manufacturer's  standard  details. 

GAUGES:  A  special  compound  gauge  for  Webster  Modulation  System  is  to  be  installed 
for  each  boiler.  This  gauge  will  be  furnished  by  the  manufacturers  of  the  system. 

RADIATORS:  All  radiators  throughout  the  building  shall  be  of or  equal 

approved  make;  all  radiators  to  be  of  the  hot-water  type  with  supply  tapping  at  top  and 
return  tapping  eccentric  at  diagonally  opposite  lower  corner.  Radiators  to  be  of  the  height 
and  columns  and  to  contain  the  surface  indicated  on  plans.  In  no  case  is  radiation  to  pro- 
ject above  window  sill.  In  connecting  all  radiators,  the  inlet  end  shall  be  placed  next  to 
feed  risers,  if  possible. 

The  indirect  stacks  are  to  be  (make  and  type)  cast-iron  radiation,  to 

be  of  the  size  and  contain  the  number  of  sections  as  called  for  on  plans. 

The  heating  contractor  is  to  instruct  the  manufacturer  of  the  radiation  that  same  is 
to  be  thoroughly  pickled  and  cleaned  before  shipment  and  that  the  outlets  are  to  be  plugged 
with  loose  wooden  plugs.  The  manufacturer  must  issue  his  certificate  to  the  contractor 
showing  that  these  radiators  have  been  so  cleaned.  These  radiators  are  to  be  kept  plugged 
until  they  are  installed  and  connected. 

Air  valve  tappings  are  to  be  plugged. 

Radiators  must  be  tapped  or  bushed  for  sizes  of  supplies  and  returns  as  shown  on  plans. 

HANGERS:  Hangers  for  indirect  stacks  are  to  be  strong  wrought-iron  or  pipe  supports. 

ENCLOSURES  FOR  RADIATORS:  The  enclosures  and  grilles  for  enclosed  radiators  will  be 
furnished  by 

RETURN  TRAPS:  The  return  end  of  every  radiator,  pipe-coil  or  other  form  of  heating 
unit  must  be  provided  with  a  Webster  Return  Trap  (of  the  type  selected).  The  size  of  the 
trap  for  each  radiation  unit  shall  be  as  shown  on  plan  or  called  for  in  specification.  The 
connections  of  Webster  Return  Traps  must  be  made  to  the  approval  of  Warren  Webster 
&  Company,  who  will  provide  the  contractor  with  service  details  showing  approved  forms 
of  connection. 

SUPPLY  VALVES:  Each  radiation  unit  must  be  provided  with  a  Webster  Modulation 
Valve  connected  to  the  top  supply  tapping. 

*  To  be  inserted  in  case  the  Architect  or  Engineer  desires  to  obtain,  for  comparative  purposes,  an  alternate  price  .upon  ap- 
paratus of  a  make  oth«r  than  Webster 

290 


The  sizes  of  supply  valves,  the  radiator  tappings  and  the  sizes  of  horizontal  branches 
from  risers  to  radiators  must  be  as  shown  on  plans. 

Kach  overhead  radiator  must  be  provided  with  a  Webster  Modulation  Valve  with  chain 
attachment. 

Provide  a  Webster  Modulation  Extended-stem  Valve  for  each  radiator  behind  a  grille. 

MODULATION  VENT  TRAP:   Furnish  and  install  [one]  No Webster  Modulation 

\ciil  Trap  for  separating  the  air  from  the  condensation  in  the  heating  system.     [The] 

[Kach]  trap  is  to  be  vented  through Webster  Vent  Valve[s]  placed  in  the  top. 

PIPE:    All  pipe  must  be  full-weight  [mild-steel]  [genuine  wrought  iron]  equal  to  that 

manufactured  by All  screwed  piping  must  be  fitted  with  occasional 

flanged  unions.    Where  supply  pipes  are  reduced  in  the  run,  eccentric  reducing  couplings 
must  be  used. 

Straighten  all  pipe,  ream  all  burrs  and  remove  all  dirt  before  erecting  pipe  or  fittings. 
Have  all  runs  plumb  and  parallel  with  building.  Allowance  for  expansion  and  contraction 
must  be  provided.  Support  all  pipes  securely  and  in  such  manner  as  to  permit  unobstructed 
movement  between  anchorages  for  expansion  and  contraction. 

So  far  as  possible,  all  horizontal  runs  must  be  graded  in  the  direction  of  steam  flow; 
where  this  is  not  possible,  the  pipe  lines  shall  be  materially  increased  in  size  as  shown  on 
plans. 

FITTINGS:  All  fittings  shall  be  best  gray-iron,  straight  and  true  and  free  from  holes  or 
other  defects;  equal  to  those  manufactured  by Fittings  shall  be  standard- 
weight. 

VALVES:  All  gate  valves  must  be  equal  to  those  manufactured  by All 

check  valves  must  be  special,  of  balanced  type  with  vertical  seat,  and  of  approved  make. 

FRESH-AIR  INLETS:  Fresh-air  inlets  for  indirect  heating  are  to  be  taken  from  openings 
provided  in  walls.  Another  contractor  will  provide  heavy  copper  wire  screens  having  J^-in. 
mesh,  and  sheet  metal  louvers  over  the  mouth  of  each  inlet. 

SHEET  METAL  WORK:  The  ducts  supplying  fresh  air  to  the  indirect  stacks,  the  indirect 
stack  casings  and  the  hot-air  flue  from  indirect  stacks  to  registers  are  to  be  made  of  gal- 
vanized iron.  They  are  to  be  properly  braced  and  locked  tight  to  prevent  air  leakage. 
An  adjustable  lock  quadrant  hand  damper  is  to  be  provided  in  cold-air  connection  to  each 
indirect  stack. 

The  metal  used  for  all  ducts  and  flues  is  to  conform  to  the  following  gauges: 
Ducts  that  have  one  dimension  over  48  in.,  ...  gauge. 
Ducts  that  have  one  dimension  from  30  to  48  in.,  . . .  gauge. 
Ducts  that  have  one  dimension  from  12  to  30  in.,  . . .  gauge. 
Ducts  that  have  one  dimension  smaller  than  12  in.,  . . .  gauge. 

The  indirect  stack  casings  are  to  be  made  of  ...  gauge  iron  and  are  to  be  built  neatly 

around  stacks  and  provided  with  cleanout  doors  above  and  below  radiators  in  bottom  or  side. 

REGISTERS:   The  registers  for  the  outlets  of  hot-air  flues  from  indirect  stacks  will  be 

furnished  by ;  their  installation  is  included  within  this  contract. 

STEAM  PIPING:  From  the  steam  outlets  on  boiler  rise  and  connect  to  a  steam  header 
over  boiler.  From  top  of  header  take  branches  as  shown.  The  steam  lines  are  to  be  run 
close  to  ceiling  of  cellar  with  a  grade  of  1  in.  in  25  ft.  The  branches  for  risers  are  to  be  taken 
from  top  of  mains.  Steam  header  and  main  are  to  be  dripped  to  wet  drip  line  where  shown. 
RISERS:  A  system  of  supply  and  return  risers  is  to  be  run  as  shown.  Risers  are  to  be 
run  [exposed]  [concealed],  and  are  to  be  of  sizes  marked  on  plans.  Unless  otherwise  noted 
on  plans,  branches  to  radiators  above  first  floor  are  to  be  run  concealed  in  floor  construc- 
tion and  branches  to  first  floor  radiators  are  to  be  run  overhead  in  cellar  as  close  to  ceiling 
as  possible.  All  radiator  branches  are  to  grade  back  to  risers  or  mains  with  as  much  grade 
as  possible,  in  no  case  less  than  1  in.  in  5  ft.  All  connections  are  to  be  made  with  ample 
provision  for  expansion  and  contraction  and  particular  care  is  to  be  taken  thai  branches  are 
run  without  pockets. 

RETURN  PIPING  :  All  return  risers  and  returns  from  first  floor  radiators  are  to  connect 
into  overhead  return  mains.  The  return  mains  are  to  start  as  high  as  possible  and  grade 
toward  the  Webster  Modulation  Vent  Trap  1  in.  in  25  ft.  The  vent  trap  (or  traps)  to  be 
located  where  shoiun  and  at  least  30-in.  above  the  ivater  line  and  as  much  higher  as  possible. 

291 


[The]  [Each]  vent  trap  will  be  provided  with  a  tapping  near  the  top  into  which  the  dry 
return  main  must  be  connected,  a  tapping  in  the  bottom  from  which  a  ...  in.  pipe  must 
be  run  to  below  boiler  water  line  and  connected  into  the  wet  return  through  a  horizontal 

swing  check  valve  of make.    Make  a  full  size  bypass  connection  around  [each] 

vent  trap.  Make  a  . .  .-in.  city  water  supply  connection  to  boiler  with  check  valve  and 
cock,  also  a  ...  -in.  drain  to  waste  through  gate  valve  from  the  return  header  of  boiler  as 
directed.  Check  valves  are  to  be  installed  where  shown. 

A  wet  drip  line  is  to  be  run  on  wall  near  floor  as  shown,  and  connected  to  boiler.  To 
this  line  connect  drips  of  mains,  indirect  radiators  and  lines  from  vent  trap  as  shown. 

COVERING  :  After  all  piping  and  apparatus  has  been  tested  and  made  tight  to  the  ap- 
proval of  the  [architect]  [engineer],  the  following  covering  is  to  be  applied.  (Here  specify 
necessary  covering  for  boilers,  and  all  steam,  return  and  drip  piping,  valves  and  fittings.) 

PAINTING  AND  BRONZING  :  All  radiators,  coils  and  exposed  piping  throughout  the  build- 
ing, after  being  tested,  are  to  be  [painted]  [bronzed]  as  follows:  All  radiators,  coils  and 
exposed  piping  throughout  the  building  are  to  be  painted  one  coat  of  sizing  and  then 
bronzed  or  painted  [two]  coats ;  color  as  selected  by  architect  or  owner. 

All  exposed  parts  of  boiler  to  be  painted  two  coats  of  black  asphaltum  paint. 

Radiators  or  ducts  which  are  visible  through  grilles  or  registers  are  to  be  painted  two 
coats  of  dull  black. 

TESTS:  All  concealed  pipes  and  risers  shall  be  tested  and  made  tight  under  an 
hydraulic  pressure  of  50  Ib.  per  sq.  in.  before  being  covered  in.  The  entire  system  shall 
be  tested  under  10  Ib.  steam  pressure.  The  entire  system  shall  be  thoroughly  washed 
out  before  final  test,  wasting  condensation  to  sewer  or  other  point  of  disposal. 

CLEANING  BOILERS:  Remove  safety  valve,  place  inside  the  boiler  a  sufficient  quantity 
of  soda  ash  to  cause  saponification  of  oils  and  grease.  Run  temporary  overflow  pipe  to  waste, 
from  safety  valve  outlet  or  from  highest  point  of  boiler  and  start  moderate  fire  so  that  foam- 
ing of  boiler  will  cause  flow  of  oil  and  grease  to  waste,  at  the  same  time  feeding  the  boiler 
with  water  to  prevent  injury  to  same.  After  thoroughly  boiling  out  the  boiler,  draw  the 
fire  and  when  cool  draw  off  all  water  from  the  boiler  and  thoroughly  wash  same  with  clean 
water  to  remove  dirt  and  chemicals.  The  treatment  of  boiler  should  be  repeated  if  water 
line  fluctuates  abnormally  or  shows  signs  of  foaming. 

FUEL  AND  LABOR:  The  heating  contractor  will  furnish  all  fuel  and  labor  required 
for  testing  and  adjusting  boilers  and  apparatus  and  for  drying  out  covering  on  boilers  (and 
smoke  breeching).  He  will  also  remove  water  and  ashes  resulting  therefrom. 

TEMPORARY  SETTING  OF  RADIATORS  :  Upon  written  request  of  the  [architect]  [engineer] 
the  contractor  shall  connect  up  for  temporary  heat  such  radiators  as  shall  be  designated. 
These  radiators  shall  afterwards  be  disconnected,  moved,  cleaned,  and  afterwards  recon- 
nected permanently.  Wall  radiators  and  radiators  without  leg  sections  shall  be  supported 
on  wooden  blocks.  Each  radiator  is  to  have  two  pipe  connections  and  no  supply  or  return 
valves  are  to  be  attached  at  this  time.  Each  bidder  will  state  in  his  proposal  a  unit  price 
which  he  will  charge  for  making  temporary  connections  as  described  above. 

INSPECTION  :  This  work  is  to  be  inspected  by  a  representative  of  the  manufacturer  of 
the  return  traps  before  acceptance  and  he  shall  submit  a  written  report  of  the  same  to  the 
Architects. 

GUARANTEE:  The  contractor  must  agree  to  make  good  at  his  own  expense  any  defects 
in  labor  or  material  furnished  by  him  for  this  work  which  may  develop  within  one  year  from 
the  completion  of  this  contract,  reasonable  wear  and  tear  excepted. 

The  entire  system  when  completed  is  to  be  tested  in  the  presence  of  the  architect  or 
his  representative,  and  made  tight  without  caulking.  The  contractor  will  be  held  liable 
for  any  damage  to  the  building  or  its  contents  due  to  leaks  or  other  defects  in  his  work 
which  may  develop  during  the  period  of  installation  and  test. 


292 


CHAPTER  XXVI 


Webster  Sylphon  Trap  Attachments 

1.  For  "Sylphonizing"  Webster  Traps  of  Earlier  Types 

STEAM  heating,  like  almost  every  other  science,  has  developed  pro- 
gressively through  experience. 
Being  pioneers  in  this  field  Warren  Webster  &  Co.  have  had  ample 
incentive  and  opportunity  for  experimental  research  and  development, 
and  have  constantly  improved  their  product  and  methods,  discarding  and 
abandoning  earlier  types  of  apparatus  as  improved  forms  were  adopted. 
The  Webster  Sylphon  Trap  (shown  and  described  on  pages  242-5)  is 
now  generally  recognized  by  leading  architects  and  engineers  to  be  the 
most  satisfactory  type  of  device  for  return  line  systems.     It  is  in  its  eleventh 
year  of  success  and  the  total  number  in  use  has  passed  the  million  mark. 

Owners  of  buildings  and  plants  in  which  old-style  Webster  Valves  are 
in  use  will  be  vitally  interested  in  knowing  that  such  valves  can  be  readily 
converted  into  Webster  Sylphon  Traps  by  means  of  the 
Webster  Sylphon  Attachments  described  in  this  chapter. 
The  conversion  necessary  to  bring  the  heating  system 
thoroughly  up  to  date  can  be  made  at  a  very  moderate  cost. 
No  breaking  or  touching  of  pipe  connections  is  involved,  as 
the  old  valve  bodies  are  utilized. 

The  advantages  to  be  derived  from  the  "changeover" 
\\  ill  be  evident  from  the  description  of  the  Webster  Sylphon 


Kig.  26-1.    The  iNo.  122  Thermostatic  Valve  in  its  original  form  and  same  valve  changed  over. 

Pipe  connections  untouched 
293 


Trap,  on  page  242,  which  description  will  equally  fit  the  earlier  Webster 
Valves  after  they  are  converted  by  means  of  Webster  Sylphon  Attachments. 
The  time  required  for  changing  over  any  valve  is  only  a  few  minutes. 

CONVERSION  OF  No.  422  WEBSTER  THERMOSTATIC  VALVES:  The 
method  of  changing  over  by  means  of  the  5- A- 13  Webster  Sylphon  Attach- 
ment is  indicated  by  the  illustrations. 

It  is  only  necessary  to  remove  the  old  bonnets  and  interior  parts,  tap- 
ping the  body  for  the  insertion  of  a  new  brass  seat  by  means  of  a  tapping 
tool.  The  Webster  Sylphon  Trap  Attachment  may  then  be  inserted  and 
the  old  valve  has  become  a  new  Webster  Sylphon  Trap  equal  in  performance 
to  the  standard  Webster  Sylphon  Traps  which  are  furnished  to  thousands 
of  new  customers  each  year. 

For  conversion  of  Multiple-unit  Thermostatic  Valves,  see  page  296. 

CONVERSION  OF  WEBSTER  MOTOR  VALVES:  This  is  practically  the 
same  as  with  the  No.  422  Webster  Thermostatic  Valve  except  that  a  slightly 
different  Sylphon  Attachment  is  used. 

The  illustrations  show  the  No.  522  M  Sylphon  Attachments  for  Y^-m. 
motor-valves  of  the  disc-air-port  type.  The  No.  533  M  Attachment  for 
%-in.  motor-valves  is  of  exactly  the  same  construction.  These  same 
Sylphon  Attachments  may  be  applied  to  the  '03  motor-valves  of  the  pin- 
air-port  type  where  this  special  type  of  valve  is  to  be  changed  over. 

For  conversion  of  Multiple-unit  Motor  Valves,  see  page  296. 


Fig.  26-2.  Hi-Inch  Webster  Motor-Valve,  Disc- Port 
Type,  in  its  original  form  and  same  valve  changed  over. 
Pipe  connections  untouched 


CONVERSION  OF  No.  422  WEBSTER  WATER-SEAL  MOTORS:  The 
method  of  changing  over,  as  illustrated,  involves  the  use  of  the  same  attach- 
ment as  for  changing  over  the  Webster  Thermostatic  Valve  as  just  de- 
scribed. In  the  case  of  the  Water-seal  Motor,  however,  the  operation  is 
simplified  through  the  old  body  being  already  tapped  for  the  valve  seat. 

It  is  only  necessary  to  remove  the  old  bonnets  and  interior  parts,  and 
insert  the  new  brass  seat.  The  Webster  Sylphon  Trap  Attachment  may 
then  be  inserted  and  the  old  valve  becomes  a  new  Webster  Sylphon  Trap. 

For  conversion  of  Multiple-unit  Valves,  see  page  296. 

294 


Fig.  26-3.  The  No.  422  Water-seal  Motor  in 
its  original  form  and  same  motor  changed 
over.  Pipe  connections  untouched 


, 

yr 


Fig.  26-4.  No.  5-C-15  Sylphon  Attach- 
ment for  522  or  523  Water-seal  Trap 
where  the  discharge  rating  is  low 


CONVERSION  OF  No.  522  WATER-SEAL 
TRAPS:  The  change-over  in  this  instance  re- 
quires only  removal  of  the  old  bonnets  and 
interior  parts,  and  inserting  the  new  Webster 
Sylphon  Trap  Attachments. 

Re-tapping  is  not  necessary  for  the  new 
seat. 

For  conversion  of  Multiple-unit  Water- 
seal  Traps,  see  page  296. 

Similar  Webster  Sylphon  Attachments  can 
be  furnished  for  all  the  other  sizes  of  Webster 
Water-seal  Traps  as  follows: 

%-in.— No.  523 
%-in.— No.  533 
1-in.— No.  534 
1-in.— No.  544 
£i    1%-m. — No.  545 


Fig.  26-5.    No.  ~>-'2  \\olisli-r  Water-seal  Trap  in  its  original  form  and  siime  trup  changed  over, 
H'2  S\lphon  VtUichraent  for  higher  discharge  rating 

295 


The  No.  522  and  No.  523  take  the  same  Sylphon  Attachment.  Another 
attachment  applies  equally  for  No.  533  and  No.  534.  No.  544  and  No.  545 
each  have  an  individual  attachment. 


2-Unil 


5-Unit 


6-Unit 


Fig.  26-6.    Multiple-unit  Thermostatic  Valve  with  No.  4  Type  bodies  changed  over  by  means  of  Webster 

Sylphon  Attachments.     Pipe  connections  untouched.     Note  how  intervening  openings 

are  blanked  out  by  new  cap  and  solid  seat 

CONVERSION  OF  MULTIPLE-UNIT  WEBSTER  VALVES  OF  EARLIER  TYPES  : 
On  units  of  radiation  beyond  the  capacity  of  a  single  valve  it  was  the  practice 

296 


in  the  past  to  recommend  and  use  a  Multiple-unit  Valve,  made  up  of  a 
special  body  having  multiple  openings  to  receive  two  or  more  bonnets 
similar  in  all  respects  to  those  used  in  the  standard  single-unit  valve. 

For  changing  these  Multiple-unit  Webster  Valves  by  means  of  Sylphon 
Attachments,  the  use  of  Sylphon  Attachments  is  recommended  only  for  the 
alternate  openings  in  the  valve  body,  the  intervening  outlets  being  plugged 
as  shown  in  Fig.  26-6. 

Multiple  Valves  were  made  up  to  6-unit.  It  is  necessary  to  deter- 
mine whether  attachments  are  for  2-unit,  3-unit,  etc.,  so  that  proper  num- 
ber of  attachments,  solid  seats  and  blanking-out  caps  may  be  furnished. 

The  Multiple-unit  Valve,  when  changed,  will  have  capacity  equal  to 
(and  possibly  in  excess  of)  the  requirements  of  the  original  installation. 

r 

II.  For  "Sylphonizing"  Radiator  Outlet  Valves  of  Other  Makes 


Fig.  26-7.  5-A  Extension  Attachments  (Five-fold  Sylphon  bellows)  applied  to  valve  bodies  of  various  makes 

297 


A  great  demand  has  developed  for  Webster  Sylphon  Attachments, 
not  only  in  connection  with  early  types  of  Webster  Valves,  but  for  other 
makes  of  valves  and  traps,  and  in  the  converting  of  old  gravity  systems  in 
which  the  ordinary  hand-wheel  shut-off  valve  was  employed. 

To  meet  the  requirements  of  a  wide  variety  of  sizes  and  types  of  valve 
and  trap  bodies  the  Attachments  described  in  the  following  pages  have  been 
designed.  The  principle  is  the  same  with  each  attachment.  The  variation 
is  only  in  the  work  of  application. 

With  the  instructions  furnished  and  the  tools  loaned  for  the  purpose, 
the  work  of  Websterizing,  by  means  of  these  attachments,  is  so  simple  that 
it  can  be  done  in  a  few  minutes  for  each  radiator,  and  so  cleanly  that  there  is 
no  disturbance  or  damage  to  surroundings  or  furnishings. 

The  use  of  these  Webster  Sylphon  Attachments,  properly  applied 
throughout  the  building,  will  often  effect  the  same  advantages  as  extensive 
changes  in  piping  and  at  a  small  fraction  of  the  cost.  And  further,  the 
whole  work  of  change-over  can  be  done  without  interrupting  the  operation 
of  the  system  as  a  whole. 

Series  18  Webster  Sylphon  Attachments  are  of  two  general  forms: 

Class  A  in  which  the  attachment  parts  are  fitted  in  an  extension  body 
which  screws  into  the  old  trap  or  valve  body ;  and  Class  C  in  which  the  at- 
tachment parts  are  fitted  into  a  special  brass  cap  which  is  threaded  to  fit 
the  old  valve  or  trap  body. 

Tne  Class  'A~  Extension  AttachrnerrR?  are  made  with  extension  bodies 
to  receive  5-fold  Sylphon  Bellows  (symbol  5-A)  and  to  receive  12-fold 
Sylphon  Bellows  (symbol  12- A). 

The  extension  bodies  of  both  the  5-A  and  12- A  classes  are  made  with  a 


Fig.  26-8.    Typical  Class  A  Sylphon  Attachments  having  extension  bodies.    Where  necessary  for  securing 
correct  final  adjustment,   a  screw  fit  or  push  fit  seat  is  used.     A  typical  push  fit  seat  is  shown  at  the  right. 

298 


Fig.  26-9.    Typical  Extension  bodies  12-A 

threaded  opening  at  the  top  to  receive  a  standard  cap,  but  of  varying  diam- 
eters of  the  lower  part  of  the  body,  so  that  the  lower  end  may  be  threaded 
to  fit  the  thread  of  the  old  body. 

The  illustrations  show  the  full  series  of  Extension  Attachments  from 
5-A-12  to  5-A-27  inclusive.  The  12-A  Extension  Attachments  are  similarly 
made  in  sizes  12-A-12  to  12-A-27  inclusive,  although  the  application  of  only 
two  of  this  type  is  shown. 

The  capacity  required  as  indicated  by  size  of  radiator  determines 
whether  a  5-A  or  12-A  Extension  Attachment  should  be  used. 

It  will  be  noted  that  the  valve  stem  attached  to  the  Sylphon  Bellows 
varies  in  length  with  the  type  of  valve  body,  but  is  similar  in  all  cases. 

The  seat  requires  a  little  explanation.  It  is  impractical  to  use  a  threaded 
seat,  as  a  constant  distance  must  be  maintained  from  body  face  to  seat  face 
and  this  cannot  be  done  with  a  threaded  seat  because  of  the  variations  in 
the  distance  mentioned,  which  will  occur  in  bodies  of  same  make  and  size. 

The  seat  is  made  to  push-fit  in  the  body  opening  which  is  previously 
prepared  by  reaming  to  the  desirable  diameter.  Final  attachment  to  gauge 
depth  to  meet  any  variation  in  the  depth  of  the  valve  body  is  made  by 
means  of  a  push-in  tool  which  is  loaned  for  the  purpose. 

In  the  case  of  ordinary  globe  or  angle  valve  bodies  and  in  various  makes 
of  float  traps  where  preparation  in  this  respect  was  not  previously  provided, 
the  push-fit  seat  described  above  provides  means  to  obtain  the  correct 
final  adjustment  without  difficulty. 

The  valve  stem  is  a  solid  brass  rod  with  a  conical  taper  for  seating  and 
is  of  varying  length  as  determined:  (1)  by  the  gauge  depth  of  the  old  body 
from  bonnet  face  to  seat,  (2)  by  the  diameter  of  orifice  in  the  seat;  and  (3) 
by  the  rating  of  the  radiation  unit  to  which  the  valve  is  connected.  Where 
necessary  to  provide  greater  vapor  space  through  the  neck  of  the  extension 
body,  the  rod  is  turned  down  to  smaller  diameter  at  such  points. 

The  Class  C  Cap  Sylphon  Attachments  are  designed  for  those  forms 
of  old  valve  and  trap  bodies  in  which  the  expanding  member  (Sylphon 
Bellows)  and  conical  valve  piece  may  be  placed  entirely  w  ithin  the  old  body 
without  the  use  of  an  extension  body. 

With  this  class  of  attachment  it  is  necessary  to  provide  a  special  cap, 
threaded  to  fit  the  existing  body,  but  the  design  has  been  standardized  so 
that  few  patterns  need  be  used  to  meet  a  wide  variety  of  bodies. 

290 


Fig.  26-10.  Typical  Class  C  Sylphon 
Cap  Attachments  placed  entirely  with- 
in the  old  bodies  and  push-fit  seats  in- 
stalled for  correct  final  adjustment 

At  the  left  is  a  5-C  Attachment 
(Five-fold  Sylphon  bellows) 

At  the  right  is  a  12-C  Attachment 
(Twelve-fold  Sylphon  bellows) 

Note  this  special  case  of  a  new 
screwed-in  seat  with  a  pushed-in  fer- 
rule for  insuring  accurate  adjustment 


The  Class  C  Cap  Attachments,  like  the 
Extension  Attachments,  are  made  to  receive 
either  the  5-fold  or  12-fold  Sylphon  Bellows  to  \>  ^l 

which  the  symbols  5-C  and  12-C  are  given. 

The  illustrations  above  show  the  applica- 
tion of  Class  C  Cap  Attachments  to  two  differ- 
ent shapes  of  valve  bodies. 

The  description  given  previously  in  refer- 
ence to  the  valve  stem  and  seat  for  the  Extension  Attachments,  applies 
equally  to  the  Cap  Attachments. 


300 


CHAPTER  XXVII 

Fuel  Saving  by  Preheating  Boiler-Feed  Water 

WHERE  exhaust  steam  is  available  and  would  otherwise  be  wasted, 
a  considerable  saving  of  fuel  may  be  effected  by  utilizing  a  direct- 
contact  (open)  feed-water  heater  to  transfer  heat  from  the  exhaust 
steam  to  the  cold  feed  water. 

The  saving  amounts  to  approximately  one  per  cent  of  fuel  for  each  11 
deg.  increase  in  the  feed-water  temperature.  This  is  the  figure  taken 
for  ordinary  calculations. 

A  more  accurate  method  of  computing  this  saving  takes  into  considera- 
tion the  total  heat  in  the  steam  generated  in  the  boiler,  as  well  as  the  final 
and  initial  temperatures  of  the  feed  water. 
This  formula  is 

Total  saving  in  per  cent  =  7         '     -^- ,  in  which  H=  total  heat  above 

n.  -\-  •>—  — tj 

32  deg.  fahr.  per  Ib.  of  steam  at  boiler  pressure,  t,=  temperature  of  water 
after  heating,  and  ts=  temperature  of  water  before  heating. 

Table  27-1.    Percentage  of  Total  Heat  of  Steam  Saved  per  Degree  Increase  in 
Feed-water  Temperature  for  Various  Pressures  of  Saturated  Steam 

Gauge  pressure  in  boiler — Lb.  per  sq.  in. 

gt  0 10  25  50  75  100          125          150          175          200  225 

f£  Value  of  H 

I  £  1150.4  1160.2  1169.2  1178.4  1184.3  1188.8  1192.2  1195.0  1197.3  1199.2  12Q8.» 


CM 

32 
40 

.0869 
.0875 

.0862 
.0868 

Per  cent  saved  per  degree  increase  in  temperature 
.0855   .0849   .0844   .0841   .0839   .0837   .0835 
.0861   .0854   .0850   .0847   .0844   .0843   .0841 

.0834 
.0840 

.  0833 
.0839 

50 

60 
70 

.0883 
.0891 
.0899 

.0875 
.0883 
.0891 

.0869 
.0876 
.0884 

.0862 
.0869 
.0877 

.0857 
.0865 
.0872 

.0854 
.0862 
.0869 

.0852 
.0859 
.0866 

.0850 
.0857 
.0864 

.0848 
.0855 
.0863 

.0847 
.0854 
.0861 

.0846 
.0853 
.0860 

80 
90 

100 

.0907 
.0915 
.0924 

.0899 
.0907 
.0916 

.0892 
.0900 
.0908 

.0884 
.0892 
.0900 

.0880 
.0888 
.0896 

.0877 
.0884 
.0892 

.0874 
.0882 
.0889 

.0872 
.0879 
.0887 

.0870 
.0878 
.0886 

.0869 
.0876 
.0884 

.0867 
.0875 
.0883 

110 
120 
130 

.0932 
.0941 
.0950 

.0924 
.0933 
.0941 

.0916 
.0925 
.0934 

.0909 
.0917 
.0925 

.0904 
.0912 
.0921 

.0900 
.0909 
.0917 

.0897 
.0906 
.0914 

.0895 
.0903 
.0912 

.0893 
.0902 
.0910 

.0892 
.0900 
.0908 

.0891 
.0899 
.0907 

140 
150 
160 

.0959 
.0968 
.0978 

.0950 
.0959 
.0969 

.0942 
.0951 
.0960 

.0934 
.0943 
.0952 

.0929 
.0938 
.0947 

.0925 
.0935 
.0943 

.0922 
.0931 
.0940 

.0920 
.0929 
.0937 

.0918 
.0927 
.0935 

.0916 
.0925 
.0934 

.0915 
.0924 
.0932 

170 
180 
190 

.0987 
.0997 
0.1008 

.0978 
.0988 
.0998 

.0970 
.0979 
.0989 

.0961 
.0970 
.0980 

.0956 
.0965 
.0974 

.0952 
.0961 
.0970 

.0948 
.0957 
.0967 

.0946 
.0955 
.0964 

.0944 
.0953 
.0962 

.0942 
.0951 
.0960 

.0941 
.0950 
.0959 

200 
210 

220 

0.1018 
0  1028 
0  1039 

0.1008 
0.1018 
0.1029 

.0999 
0.1009 
0.1019 

.0990 
0999 
0.1010 

.0981 
.0991 
0.1001 

.0980 
.0990 
.0999 

.0976 
.0986 
.0996 

.097t 
.0983 
.0993 

.0972 
.0981 
.0991 

.0970 
.0979 
.0989 

.0968 
.0978 
.0987 

301 


Example:  Assume  a  boiler  pressure  of  140  Ib.  per  sq.  in.  absolute,  and 
initial  and  final  temperatures  of  40  deg.  fahr.  and  210  deg.  fahr.  respectively. 
The  total  saving  according  to  this  formula  is  14.36  per  cent,  where  by  the 
"one  per  cent  for  each  11-deg.  increase"  rule,  the  saving  for  the  same  condi- 
tions figures  15.45  per  cent. 

For  convenience  the  results  as  figured  from  the  more  accurate  formula 
have  been  reduced  in  Table  27-1,  to  a  basis  of  per  cent  of  saving  per  degree 
increase  of  temperature. 

WEBSTER  FEED-WATER  HEATERS:  Webster  Feed-water  Heaters,  for 
obtaining  the  fuel  savings  just  mentioned  and  other  benefits  not  so  easily 
measured ,  are  made  in  the  following  types : 

Series  100,  Class  B,  with  overflow  seal:  The  standard  type  for  utilizing 


Fig.  27-1.     Series  100  Class  B 
Webster  Feed -water  Heater 


Fig.  27-3.     Series   400   Class  EBP  and 

Fig.  27-2.  Series  200  Class  EB  and    Series  500  Class  EBPH  Webster  Feed- 
Series  300  Class  hBH  Webster  teed-   water  Heater.  Preference  Cut-out  Type 
water  Heater.     Standard  Type. 
Smaller  sizes 


Fig.  27-4.  Series  800  Class  EF  Webster 
Feed-water  Heater,  Standard  Type 


Fig.  27-5.    Series  900  Class  EFP  Webster  Feed- 
water  Heater.    Preference  Cut-out  Type 

302 


exhaust  steam  at  atmospheric  pressure  and  for  a  maximum  steam  pressure 
of  J^-lb.  per  sq.  in.  May  be  operated  on  either  induction  or  thoroughfare 
principle. 

Series  200,  Class  EB:  The  standard  type  for  use  in  connection  with  ex- 
haust steam  systems  under  pressures  not  exceeding  5-lb.  per  sq.  in.  Best 
operated  on  induction  principle. 

Series  300,  Class  EBH:  Same  as  Series  200,  Class  EB,  but  suitable  for 
pressures  up  to  10-lb.  per  sq.  in.  maximum.  Tested  to  15-lb.  per  sq.  in. 

Series  400,  Class  EBP:  Same  as  Series  200,  Class  EB,  but  with  inde- 
pendent oil  separator  large  enough  to  purify  all  exhaust.  Specially  designed 
for  use  with  exhaust  steam  heating  or  drying  systems  under  pressures  not 
exceeding  5-lb.  per  sq.  in. 

Series  500,  Class  EBPH:  Same  as  Series  400,. Class  EBP,  bu4^suitable 
for  pressures  up  to  10-lb.  per  sq.  in.  maximum.  Tested  to  15-lb.  per  sq.  in. 

Series  800,  Class  EF:  This  type  is  for  smaller  capacities,  50  to  350 
hp.,  and  is  similar  to  Series  200,  Class  EB,  except  that  the  shell  is  a  one- 


Multiply  Maximum  Back  Pressure 
carried  in  Heater  by  3  to  determine 

least  Dimension  in  Feet 
Water  Inlet  Valve 


Note:- 

The  Area  of  Pipe  6 
to  be  twice  that  ot 
Pipe  A 


Note:- 

With  Reciprocating  Type  Boiler  Feed  Pumps 
allow  at  least  24  inches  (as  much  more  as 
practicable)  from  C.L.  ol  Suction  Outlet  to 
Pump  Valves.  With  Centrifugal  Pumps 
Consult  Pump  Manufacturer. 

To  Boiler  Feed  Pump 


3  To  Sewer 


Fig.  27-6.    Webster  Feed-water  Heater  installation  in  connection  with  a  Vacuum  Heating  System.    Water 
inlet  automatically  controlled.  The  heater  shown  is  of  the  standard  type.   Any  other  type  of  Webster 

Heater  would  be  connected  in  the  game  way 


ana 


piece  casting  and  is  supported  by  a  framework  made  from  pipe  and  fittings. 
It  is  suitable  for  working  pressures  up  to  10-lb.  per  sq.  in. 

Series  900,  Class  EFP:  Same  as  Series  800,  Class  EF,  but  including  the 
large  size  oil  separator  and  the  cut-out  valve. 

WEBSTER  FEED-WATER  HEATERS,  STANDARD  TYPE:  The  heater  shell 
as  illustrated  in  this  chapter,  is  made  of  close-grained  cast-iron  plates.  Web- 
ster Heaters  are  also  made  with  shells  of  genuine  old-fashioned  puddled 
wrought-iron,  or  of  other  sheet  metals  such  as  flange  steel  or  the  so-called 
copper-bearing  steels.  Wrought-iron  heaters  are  specially  recommended 
as  they  are  proof  against  the  minor  accidents  of  operation  which  fre- 
quently crack  cast-iron  heaters. 

The  heater  is  easily  cleaned,  as  the  interior  is  accessible  without  dis- 
turbing any  of  the  pipe  connections.  The  large  hinged  doors  may  be  quickly 
opened,  and  the  trays  withdrawn.  The  lower  chamber,  containing  the 


Vent 


Exhaust  to 
Atmosphere 


WEBSTER 
AIR  SEPARATING  TANK 


Discharge  from 
Vacuum  Pump 


Note:- 

The  Area  of  Pipe  B 
to  be  twice  that  of 
Pipe  A 


/"* 

To  Drain 


Multiply  Maximum  Back  Pressure 
carried  in  Heater  by  3  to  determine 
least  Dimension  in  Feet 
Regulating  Valve      I  Returns  Inlet 


Notc:- 

With  Reciprocating  Type  Boiler  Feed  Pumps 
allow  at  least  24  inches  (as  much  more  as   J? 
practicable)  from  C.L.  of  Suction  Outlet  to    o> 
Pump  Valves.  With  Centrifugal  Pumps  <« 

Consult  Pump  Manufacturer. 

To  Boiler  Feed  Pump 


jTo  Sewer 


Fig.  27-7.     This  Webster  Feed-water  Heater  installation  differs  from  usual  practice  in  that  the  make-up 
water  supply  is  manually  controlled.     A  float  within  the  heater  operates  a  valve  in  the  steam-pipe  sup- 
plying the  boiler-feed  pump  to  stop  the  pump  when  the  water  level  is  below  a  pre-determined  point 


304 


filter,  is  accessible  through  the  filter  doors.  Where  the  doors  are  bolted  to 
the  heater  body,  the  shell  is  suitably  reinforced,  the  faces  being  machined 
to  insure  tight  joints. 

LOW  PRESSURE 

RETURNS  INLET    TROUGH  a  WATER  SEAL 

HEATING  TRAYS 


OIL  SEPARATOR 


EXHAUST 

STEAM  INLET 

^ — 

HIGH  PRESSURE 

1ETURNMT 


OVERFLOW 
SINK  PAN 


SKIMMER  EOR 
RFACE  BLOWOFF 


OIL 

SEPARATOR  DRIP 


SINK  PAN 
CONTROLLIN 
L 
WATER  LEVE 


OVERFLOW 
OUTLET 


ER  SCREENS 


Fig.  27-8.    Series  200  Class  EB  and  Series  300  Class  EBH  Webster  Feed-water  Heater,  Standard  Type 

305 


The  water  supply  to  the  heater  is  controlled  automatically,  the  regulat- 
ing valve  being  operated  by  a  series  of  levers  connected  to  an  open  copper 
sink  pan  (performing  the  functions  of  a  float),  placed  within  the  heater  shell. 

Any  dangerous  excess  of  water  automatically  passes  out  of  the  heater 
when  the  water  reaches  the  overflow  level.  Except  in  the  case  of  the  100 
Series,  the  excess  water  is  automatically  passed  out  through  a  valve  actuated 
in  the  same  manner  as  the  cold  water  supply-valve,  that  is,  by  another  open 
sink  pan  placed  within  the  heating  chamber.  This  valve  is  normally 
closed,  preventing  loss  of  steam. 

The  Webster  Oil  Separator  which  forms  a  part  of  each  heater  is  well 


Fig.  27-9.    Series  800  Class  EF  Webster  Feed-water  Heater,  Standard  Type 


306 


known  and  extensively  used  as  an  independent  unit  for  removing  oil  from 
exhaust  steam  mains,  hence  its  use  in  the  Webster  Feed-water  Heater. 

The  feed  water,  entering  the  heater  through  the  automatically  con- 
trolled valve  inlet,  passes  into  the  water-sealed  distributing  trough,  which 
has  two  wide,  extended  lips.  The  water,  overflowing  from  this  trough  in 
even  sheets,  is  distributed  over  a  series  of  oppositely  inclined,  finely  per- 
forated metal  trays,  arranged  one  above  the  other  as  shown  in  the  illustra- 
tion below.  The  water  in  its  downward  course  falls  from  one  tray  to  the 
other,  part  of  it  passing  through  the  tray  perforations  and  the  balance 

WATER  INLET  REGULATING  VALVE 

LOW  PRESSURE  RETURNS  INLET 

/TROUGH? WATER  SEAL 
HEATING  TRAY5 


EXHAUST 
STEAM  INLET 


BAFELE 
,  WEBSTER 
PREFERENCE 
SEPARATOR 


OVERFLOW  IK  PAN 

SKIMMER  FOR  SURFACE 
BLOWOFF 


DRAIN 
MEN  FOR  PUMP 


FILTER  SCREENS 


CHAMBER 


FILTER  CHAMBER 


Fig.  27-10.    Series  400  Class  EBP  and  Series  500  Class  EBPH  Preference 
Cut-out  Type  Webster  Feed-water  Heaters 

307 


falling  from  the  lower  edge  of  the  tray  to  the  tray  immediately  below. 

This  method  of  water  travel  provides  the  necessary  surface  contact  for 
the  steam  and  water  so  that  the  highest  possible  temperature  is  imparted  to 
the  water,  causing  a  liberation  of  gases  and  precipitation  of  solids.  Ample 
space  is  provided  for  uniform  distribution  of  steam  around  the  trays. 

By  reason  of  the  large  storage  chamber  it  is  possible  to  utilize  the  heater 
as  a  receiver  for  condensation  from  heating  systems,  dry  kilns,  heating 
apparatus,  etc.  Between  the  level  at  which  the  cold  water  supply-valve  is 
closed  and  the  overflow  there  is  ample  space  for  the  accumulation  and 
storage  of  such  returns. 

The  filter  is  located  in  the  lower  compartment  of  the  heater.  In  this 
settling  chamber,  opportunity  is  given  for  the  precipitation  and  filtration 
of  the  particles  of  sediment  and  impurities  and  for  frequent  drainage  through 
a  quick-opening  drain  valve. 

The  filter  bed  is  commonly  composed  of  coke  or  other  suitable  material, 
which  is  contained  between  the  perforated  division  screens  already  mentioned. 
This  material  can  be  renewed  whenever  necessary. 

The  large  doors  at  the  front  allow  ready  access  for  charging  and  cleaning. 

THE  WEBSTER  PREFERENCE  CUT-OUT  HEATER:  This  type,  as  may  be 
noted  from  the  illustrations,  combines  a  Webster  Heater  and  a  large  oil 
separator  with  a  cut-out  gate  valve  intervening.  The  oil  separator  has 
sufficient  capacity  to  remove  the  oil  from  the  exhaust  steam  delivered  from 
the  engines,  pumps  and  other  sources.  This  arrangement  is  therefore 
especially  desirable  where  exhaust  steam  is  to  be  utilized  in  heating  or  drying 
systems,  cooking  kettles  or  other  industrial  processes. 

A  Webster  Grease  Trap  is  used  in  draining  the  separator.  Steam  from 
the  engines  and  auxiliaries  should  be  combined  in  a  common  exhaust  pipe 
before  reaching  the  heater.  This  exhaust  pipe  may  enter  the  separator 
horizontally  or  vertically,  the  latter  condition  being  usual  with  the  exhaust 
steam  current  upward. 

Upon  reaching  the  preference  oil  separator  the  steam  flows  horizontally 
through  the  baffles,  which  are  of  the  standard  Webster  design  (see  Figure 
27-11),  comprising  a  number  of  hooked  steel  plates  interposed  in  the  course 
of  the  steam,  causing  separation  by  contact,  by  change  of  direction  and  by 
adhesion.  The  ports  through  which  the  steam  is  guided  and  the  free 
area  through  the  baffles  are  especially  designed  to  prevent  any  considerable 
loss  of  pressure. 

After  passing  through  the  baffles,  the  steam  may  pass  to  the  heater,  or 
to  the  outlet  into  the  heating  system  or  other  apparatus  using  exhaust 
steam  or  to  the  atmosphere. 

Particularly  valuable  advantages  of  the  Webster  Preference  Cut-out 
Heater  are: 

1.  The  considerable  saving  in  piping  connections  and  additional  ap- 
paratus accomplished  by  its  use  as  compared  with  the  Standard  Heater. 

2.  The  cut-out  valve  used  in  the  Webster  Preference  Cut-out   Heater 
is  most  reliable  for  its  purpose.     When  the  heater  is  cut  out  for  internal 
inspection  or  cleaning,  the  course  of  the  exhaust  steam  through  the  oil 

308 


separator  is  such  that  no  steam  is  in  contact  with  the  side  wall  of  the  heater. 
Steam  passes  through  the  separator  and  on  to  atmosphere  or  the  heating 
system  without  warming  up  the  heater  body  to  a  degree  that  would  endanger 
or  discomfort  the  man  who  may  have  to  enter.  A  thorough  clean-out  is 
possible  at  any  time  without  having  to  wait  until  the  whole  plant  is  shut 
down. 

3.  The  grease  and  oil  trap  too  is  not  integral  with  the  overflow  of  the 
heater,  so  that  if  its  outlet  becomes  temporarily  deranged,  oil  cannot  get 
back  into  the  heater  through  the  overflow  opening. 


Fi>.  27-11.     Seri.-s  900  Class  EFP  Preference  Cut-out  Type  Webster  Feed-water  Heater 


309 


Table  27-2.     Dimensions  of  Series  200,  Class  EB,  Webster  Feed-water  Heaters 
For  working  pressure  up  to  5  Ib.  per  sq.  in. 

Specifications 


Capacity 

Heating  trays 

Cubic  contents 

Weights,  Ib. 

No. 

Horsepower  * 

Lb. 

min. 

no. 

Area 
sq.    ft. 

Ma- 
terial 

Total 
cu.  ft. 

Water 
cu.  ft. 

Filter 

pres. 

Shipping 

Max. 

203 

to      400 

^N 

9247 

12.5 

24.4 

14.7 

2600 

3600 

205 

425  to      650 

9203 

16.5 

o 

40.0 

25.5 

3700 

5400 

207 

675  to      900 

jt 

9250 

24.0 

c 

60.0 

40.0 

4700 

7300 

210 

925  to    1350 

•§i 

9254 

33.0 

8 

80.5 

52.0 

g 

.S 

5700 

9000 

215 

1375  to    1850 

M 

9252 

51.6 

•J 

121.3 

80.0 

= 

8000 

13100 

220 

1875  to    2400 

ss 

9257 

63.8 

IS 

152.5 

101.  0 

"S 

$ 

9000 

15700 

225 

2425  to    3000 

9256 

82.0 

.5   CL 

180.0 

128.1 

y 
« 

10300 

18400 

230 

3100  to    4000 

=32 

22457 

95.7 

C  § 

CD 

240.0 

133.5 

e 

A 

13000 

21300 

235 

4100  to    5500 

•«  £ 

13377 

121.5 

& 

316.0 

140.0 

o 

J& 

15000 

23600 

250 

5600  to    7500 

13626 

160.1 

fij 

100.0 

179.0 

Q 

20000 

31400 

285 

7600  to    9500 

6*3 

22196 

201.5 

s 

482.0 

222.0 

22000 

36000 

299 

9600  to  12000 

2 

18779 

243.0 

268.0 

25000 

41700 

*  One  rated  horsepower=capacity  for  heating  30  Ib.  of  water  per  hour  from  40  deg.  fahr. 
to  a  temperature  within  5  deg.  of  the  steam  temperature 


D 

Returns  Inlet  — 
J          © 

^*^\ 

Lrv 

e  Steam  Drips 
® 

5-r 

<    R 
»-*- 

~~h  ^ 

Connections 
No. 

(HI 

Cold  Wat 
Inlet 

$ 

*f     f 

y> 

Exhaust  Inlet 

© 

203   6 
205   8 
207   8 
21010 

21512 
22014 
22516 
23018 

23520 

•>.-,(}  2-2 
28524 
29928 

i 
1H 

2 
2 

2H 

r 

: 

6 

5 

6 

42H 
43 

5J3M 
53H 

64 
64 

85 
86 

108 
108 
128 
1210 

\ 
1 

1M 
1M 
Di 

1J"4 

2-1H 
2-1^ 

tH 

2 

2 

fl'"' 

4 
4 

I 

32)^1 
43      1 
5,3      1 

53      I1,' 
55      1H 
55     1^ 
2-55      1>$ 

2-35     JIH 
2-35      1H 
2-46      2 
2-68     2 

.^i 

II 

^7^£ 
1* 

*^H^ 

s 

K 

Comb.  Vent  and 
Vacuum  Breaker 

©           i 
Pump  Outlet  - 

D 

3 

jt 

Oil  Separator 
Drips 

,      ® 

Overflow 

© 

c 

1 

®  DrainXt 

<-N-4«—  M—  ->j 

Fig.  27-12 

No. 


203 
205 
207 
210 


235 
250 
285 


Trays 

Foundation 

Over- 
all 

No. 

Size 

Lg.       Wd. 

Hgt. 

5 

15     x24 

35         35       80M 

5 

15)^x30  ^j 

41         41 

88 

6 

16     x36 

45         45 

101  % 

12 

10     X40H 

51         51 

101  ^ 

12 

13^x46 

57         57      115H 

12 

16^x47 

69         57      115H 

24 
18 

!ej|x47 

69         66 
93         57 

11754 
115M 

24 

15J^x47 

105         57 

120H 

48 

15^x31 

105         72 

122  Ji 

48 

15^x39 

105        89 

122% 

48 

15^x47 

105       105 

124^ 

Dimensions 


A      A' 

B 

C       D 

E 

F 

G 

H 

J       K 

L 

M 

N 

P         R 

32  i   88 
36    101 H 
42 


48  !  _ . 

60  !115l^  96 
60  1178  96 
84  116)^  96  1 77 


120 


21M  25M  16 

25VS  28%  19Hl  7Ji'    8M 

28  'A  27J4  34  21H  9j|   11 

31>3  31H  W  24H  8       10H 


27 


36       36K  41 H  27M  8^  13Ji 

41^ '45       47H   33%  lOJi   13Ji 

42       425^  46X   33H  lOJi   16 

57       55       53ji  45H  HM   12M 


96 


96 


61 


63K  51^ 
63H  51  J< 


20 
16 

36H 


All  sizes  and  dimensions  in  inches 

NOTE:    The  above  data  (except  weights)  applies  also  to  Extra-heavy  300  Series  Class  EBH  Heaters  for 
working  pressures  up  to  10  Ib.  per  sq.  in. 

MIA 


Table  27-3.  Dimensions  of  400  Series  Class  EBP  Webster  Feed-water  Heaters 

For  working  pressure  up  to  5  II,.  per  sq.  in. 
Specifications 


Capacity 

Heating  trays 

Cubic  contents 

Wkg 

WeiKhls.  Ib. 

No. 

Horsepower  * 

Lb. 

min. 

no. 

Area 

sq.  ft. 

Ma- 
terial 

Total 

cu.  ft. 

Water 
cu.  ft. 

Filter 

pres. 

Shipping 

Max. 

403 

to    400 

.X     i. 

13166 

12.5 

=  §  § 

24.4 

11.7 

"8 

3500 

4500 

405 

425  to    650 

-'•zi 

13188 

16.5 

40.0 

25.5 

1 
>  &. 

51b. 

4950 

6650 

407 

675  to    900 

•o.SgS. 

13167 

24.0 

*l-n 

60.0 

40.0 

cS 

per 

6700 

9300 

410 

925  to  1350 

Si's! 

13165 

33.0 

=  ^r 

80.5 

52.0 

!= 

sq.  in. 

8050 

11350 

415 

1375  to  1850 

ZS.  •" 

13171G 

51.6 

<s  o 

,121.3 

80.0 

0 

10800 

15900 

*  One  rated  horsepower  =  capacity  for  heating  30  Ib.  per  hour  from  40  deg.  fahr.  to  a 
temperature  within  5  deg.  of  the  steam  temperature 


Returns^ 
Inlet  ^- 


Live  Steam  Drips 

® 
Exhaust  Outlet 


DIAGRAM   FOR   PREFERENCE  OIL  SEPARATORS 

CLASS  H  CLASS  C 

-Q- 


Comb.  Vent  and 
Vacuum  Breaker 

©' 


WEBSTER 
CLASS  H 

PREFERENCE  OIL 
SEPARATOR 


WEBSTER 

CLASS  C 

PREFERENCE  OIL 

SEPARATOR 


nust  Outlet 
© 


-  Exhaust  Inlet 

0 

...    .jble  of  Dimensions 

below  refers  to  Heaters  with 

Standard  Equipment. 

Separators  smaller  or  larger 
than  Standard  will  be  furnish- 
ed if  desired.  The  table  at 
right  shows  sizes  of  all  Prefer 
ence  Oil  Separators  which 


'  \       GREASE  TRAP  can  be  used  with  this  type 
DIAGRAM  FOR  STANDARDxOverilowfTi          Heater 

\ 


80 


125 


175 


855 


335 


«75 


DIMENSIONS 


19* 


lOJj 


11 


UH 


15* 


27* 


30  ?f 


"f 


"X 


I.'* 


1'"; 


22  >f 


21H 


25  !< 


SIZE 
DRIP 


JITS 


11  V 


tM 


EQUIPMENT 


ij?.  27-13 


i 

Standard 
Equipment 

Connections 

Trays 

Foun- 
dation 

8 

8-0 

K> 

•0. 

® 

® 

® 

© 

n 

® 

® 

® 

® 

Size 

M 

•3 

If 

• 

i! 

&S 

7! 

& 

S 

It 

5J 

403 

10 

6 

1 

10 

1 

4 

24 

% 

14 

L"., 

24 

1 

5 

15     x2t 

35 

35 

80% 

405 
407 

12 
16 

8 
8 

1 

12 

16 

2 

4 
5 

3 

1 

1 

2  2 

3 
1 

3/2 

1 

1 

5 
6 

154x30% 
16     x36 

41 

41 
45 

88 

410 

18 

10 

14 

18 

2 

5 

34 

1 

2 

5 

3 

1 

1? 

10      xl():is 

51 

51 

101% 

415 

20 

12 

14 

20 

24 

6 

4 

1 

24 

5 

3 

1*4 

1? 

134x46 

57 

57 

S 

Dimensions 

t 

M 

• 

A 

A' 

B 

c 

D 

E 

F 

G 

H 

J 

K 

L 

M 

N 

0 

P 

V 

403 

Kir, 
407 

26 
32 
36 

26 
32 
36 

88  /4 

101  •"',, 

66 

72 
HI 

57% 
69', 

6% 

6  * 

93  % 

214 
25 

9 

27  * 
28'^ 

174 

204 

224 

25  % 
28% 
34 

16 

194 

214 

?H 

94 

9 

8% 
11 

104 
114 
114 

410 

12 

12 

101'  , 

84 

().  '  i 

7//6 

6 

934 

28 

154 

314 

25  4 

37 

8 

104 

13 

II.  > 

48 

48 

1154 

96 

774 

84 

7 

101% 

334 

16 

36 

284 

114 

27% 

13% 

11 

NOTE:    The  dimensions  and  data  above,  except  weights,  may  be  used  also  for  the  500  Series  Clasa  EBPH 
Extra-heavy  Pattern  Webster  Feed-water  Heaters 

311 


Table  27-4.    Dimensions  of  900  Series  Class  EFP  Webster  Feed-water  Heaters 

For  working  pressure  up  to  10  Ib.  per  sq.  in. 
Specifications 


Capacity 

Heating  trays 

Cubic  contents 

Weights,  Ib. 

No. 

Horsepower* 

Lb. 

niin. 

no. 

Area 
sq.ft. 

Ma- 
terial 

Total 
en.  ft. 

Water 

cu.   ft. 

Filter 

Wkg. 
pres. 

Shipping 

Max. 

900 

to    90 

_    _  j. 

17198 

4.5 

S  «  " 

7.1 

4.2 

o 

1675 

1925 

901 

95  to  150 

—    £3    *    * 

10837 

5.0 

8  £  c. 

9.8 

5.9 

ftfr 

—     • 

1780 

2140 

'HU>, 

155  to  225 

*o'§  *"  S. 

16724 

5.6 

"£°^  §° 

11.6 

7.3 

*S 

2200 

2600 

902 

230  to  300 

17203 

9.0 

s  it  u 

16.4 

11.08 

c.— 

2700 

3425 

Z"   4>\N  0 
C.~\j; 

•IfJs 

M 

ft 

'  One  rated  horsepower  =oapacity  for  heating  30  Ib.  per  hour  from  40  deg.  fahr.  to  a 
temperature  within  5  deg.  of  the  steam  temperature 


Returns  r H 

InletNl       _ 

© 


©Comb.  Vent  and 
Vacuum  Bleaker 


DIAGRAM   FOR  PREFERENCE  OIL  SEPARATORS 


' 


Eihaust  Inlet 

© 
Oil  Separator 

Drip 

Overflow  (4 


Note:- 

The  Table  of  Dimensions 
below  refers  to  Heaters 

with  Standard  Equipment. 

Separators  smaller  or 
arger  than  Standard  will 

be  furnished  if  desired. 


® 


DIAGRAM   FOR  STANDARD   EQUIPMENT 


The  table  at  right  shows  sizes  of  all 
Preference  Oil  Separators  which 
can  be  used  with  this  type  Heater 

Fig.  27-14 


Standard 

Connections 

Trays 

Foun- 

S'o.        8  — 

S£®®®®®®0 

® 

®   1 

Size           TM       -r         «  .5? 

55S      IS 

55  S 

^       tf        O  £ 

900 

4 

3 

5i       4        1        2         I*A     %     11A 

\y. 

IX 

Ji       4 

10x16     26     23     62 

901 

6 

4 

1           6        1        2}£     2          Ji     IJi     IH 

1H 

1           4 

10x18     28     25     68Mi 

00  11., 

« 

4 

1            8        1        3         2         Ji     IX 

!J-£ 

1           4 

10x20     28     27     72H 

902 

8 

5 

1           8       1        3         2         %     IX 

2 

IJi 

1           4 

14x23     30     30     79 

D  im  ens  ions 

Size 

no. 

A 

A' 

B 

C 

D 

E 

F 

G 

H 

J 

f. 

L 

H 

H 

0 

P 

900 

16 

18 

62 

43  K 

48 

20  v$ 

55  V4 

3¥ 

1814 

14 

7V* 

93^ 

10V* 

3¥ 

57 

8 

901 

18 

20 

68  Hi 

IT'4 

54?g 

23 

;5"s 

19  y, 

13 

<is  < 

lOJi 

n-% 

.V, 

63  y, 

9 

901H, 
902 

20 
22  H 

20 

22M 

72  J4 
79 

51 

58  1; 

23 

24^ 

WA 

71  \ 

!Ts 

5 

19H 
21 

i!S 

5S 

12j| 

r?s 

5 

o:!4 

73H 

9 

10 

All  sites  and  dimensions  in  inches 
312 


Table  27-5.     Dimensions  of  Series  800,  Class  EF,  Webster  Feed-water  Heaters 

For  working  pressure  up  to  10  Ib.  per  sq.  in. 
Specifications 


Capacity 

1     Heating  trftyt 

Cubic  conten  s 

Wkr 

Weifhta,  Ib. 

No. 

Horsepower  • 

Lb. 

mm. 

no. 

Area 

sq.  It. 

Ma- 
terial 

Total 
cu.  ft. 

Water 
cu.  ft. 

Filter 

pres. 

Shippini 

Max. 

800 
801 

to    MO 
«).">  to  150 

='f^ 

•w  ^  5  8 

iror, 

16660 

4.5 
5.0 

sill 

7.1 
9.8 

4.2 
5.9 

1* 

^C 

1125 
1450 

1400 
1850 

11(11  i. 

155  to  22r> 

°.S  2  §• 

16661 

5.6 

._.-     Q. 

11.  i 

7  3 

-  = 

=   !T 

1700 

2200 

802 

230  to  300 

0  =  ._  Z 

*l°2 

16662 

9.0 

if* 

16.4 

11.08 

3 

0  • 

2200 

2900 

•  One  rated  horsepower  —  capacity  for  heating  30  Ib.  of  water  per  hour  from  40  deg.  fahr.  to  a 


temperature  within  5  deg.  of  the  steam  temperature 


Returns  Inlet 
© 


•J  — >|  ^Live  Steam  Drips  ® 

Oil  Separator 
Drips 


Connections 


Ho. 


®®  ®    ®  ®  ®  ,©    ®    ® 


800       , 

801  4    1  2H2  "H1K1HH 
W1>14    1  3      2      NUilHH 

802  513      2      >4,1M2      1) 


Fig.  27-15 


Drain 


Trayi 


Water  line 


I    .1    M 


Dimensions 


No. 


800  4  lOllfi  39H  35 

801  4  10x18  44f 
80m  4  10x20  4SH  42 

802  4  14x23  55 H  49 


Cu. 
Th.     AT.    ft.        A 

A' 

B        C 

D        E 

_!_ 

0 

H 



K 

L 

M 

H 

o 

6  2.6  1.218  20  68H  47M  54H  23 
6  2.8  1.4  20  20  72H  »1  &8H  23 
A  3.6  1.8  22K  22K  79  56H  63H  24 


71) 


5     74 


All  sizes  anJ  dimensions  in  inches 


THE  WEBSTER-LEA  HEATER  METER:  This  apparatus  combines  the 
Webster  Feed-water  Heater  of  the  rectangular  cast-iron  type,  with  the 
Lea  V-Notch  Recording  Meter  so  arranged  that  both  may  be  operated  in 
combination  or  either  independently  of  the  other. 

Besides  heating  the  boiler  feed  w  ater  to  the  boiling  point,  this  apparatus 
indicates  the  actual  amount  of  boiler  evaporation.  Its  continuous  meter 
records  show  up  careless  or  improper  firing  methods,  leakage,  condensation 
due  to  poor  installation,  inferior  coal  and  in  other  words,  act  as  a  check  upon 
the  general  efficiency  of  the  entire  boiler  plant. 

The  charts  (Fig.  27-17)  can  be  integrated  by  means  of  a  standard 
planimeter,  and  an  integrating  attachment  giving  the  total  flow  for  any  period 
is  supplied.  The  readings  from  the  integrating  attachment  indicate  approxi- 
mately quantities  of  water  which  have  passed  over  the  weir. 

313 


Fig.  27-16.    Typical  Webster-Lea  Heater  Meter 


Where  it  is  desired  to  have  a  record  of  the  feed-water  temperature  on 
the  same  chart  with  the  meter  record,  a  special  attachment  can  be  fitted  to 
any  standard  instrument.  The  meter  chart  and  drum  are  made  wider  to 
provide  2^2  inches  for  temperature  calibrations.  This  space  has  25  equal 
divisions  calibrated  in  any  specified  50  or  100-deg.  interval. 


rt^n  ^'  ""-  -•      -%<<• 

„..,..  [/•  ,»i~  «..™ 


Fig.  27-17.    Typical  chart  from  a  Webster-Lea  Heater  Meter 

314 


Part  III— Addenda 

CHAPTER  XXVIII 

Miscellaneous  Useful  Information 

THE  tables  in  the  following  pages  cover  many  subjects  for  which  the 
Heating  Engineer  must  have  readily  available  data.     They  have  been 
selected  after  careful  consideration  and  will  be  found  reliable  and  suf- 
ficiently accurate  in  every  respect  to  meet  the  requirements  of  good  practice. 
The  tables  on  any  subject  can  be  readily  located  by  reference  to  the 
back  of  the  book,  where  they  are  included  both  in  the  general  index  and 
the  special  index  of  tables. 


Table  28-1.    Diameters  and  Weights  of  Seamless  Brass  and  Copper  Tubes  * 
Iron  Pipe  Size  and  Plumber's  Size 

Iron  pipe  size 


Regular 


Extra  heavy 


Diameter,  in. 

Weight  in 
pounds  per  foot 

Iron 
pipe 

Diameter,  in. 

Weight  in 
pounds  per  foot 

Outside 

Inside 

Brass 

Copper 

size 

Outside 

Inside 

Brass 

Copper 

.  io:. 

.281 

.246 

.259 

H" 

.405 

.205 

.353 

..",71 

.:>io 

.  375 

.  137 

.459 

%" 

.510 

.294 

.  593 

.624 

.675 

.191 

.612 

.644 

W 

.675 

.421 

.  805 

.847 

.810 

.625 

.911 

.958 

y* 

.810 

.542 

1.191 

1.253 

1.050 

.822 

1.235 

1  298 

w 

1  .  050 

.736 

1.622 

1.706 

1.815 

1.062 

1    710 

1.829 

i" 

1.315 

.951 

2.386 

2.509 

1.660 

1.368 

2.557 

2.689 

iji' 

1.660 

1.272 

3.291 

3.460 

1.900 

1.600 

3.037 

3  193 

I--/ 

1.900 

1.494 

3.986 

4.191 

2  375 

2.062 

4.017 

4  221 

••>" 

2.375 

1.933 

5.508 

5.791 

2.87:, 

2.500 

5  830 

6.130 

2'2" 

2.875 

2.315 

8.407 

8.839 

3.500 

3.062 

8.311 

8  741 

3" 

3.500 

2  892 

11.24 

11.82 

4.000 

3.500 

10.85 

11    11 

3K" 

4.000 

3.358 

13.66 

14.37 

4.500 

4  000 

12.29 

12.93 

4" 

1  .  500 

3.818 

16.41 

17.25 

5.000 

4.500 

13  71 

14.  II 

JH" 

5.000 

4.250 

20.07 

21.10 

5.563 

5  062 

15.40 

16.19 

y 

5.563 

4.813 

22  51 

23.67 

6.62.') 

6.  125 

18    11            19.39 

(,' 

6.625 

5.750 

31.32 

32.93 

7.62:> 

7.062 

2392            25.15 

-f 

7.625 

6.625 

41   22 

43.34 

8.625 

8  000 

30.0.-) 

31.60 

8' 

8  625 

7.625 

47  .  00 

49.92 

9.625 

8.937 

56.94 

38  81 

9' 

10.7.-.0 

10.019 

13.91 

16.17 

10' 

Plumber's  size 

.  <>:,  1 

.521 

.  152 

.  17.-. 

%" 

.768 

.631 

.  55  1 

.  583 

«" 

.  875 

.  Tl1!! 

.682 

717 

V*" 

1.000 

.  836 

.871 

.916 

I" 

*  American  Brass  Co. 

1.245 

1    060 

1    233 

1   297 

IV 

1  .  508 

1.311 

1  .  606 

1.689 

W 

1  .  7.V> 

1    56  t 

1.811 

1.939 

1*4" 

2.007 

1  .815 

2.123 

o  030 

9" 

315 


Table  28-2.    Dimensions  of  Standard  Wrought-Iron  Pipe* 

Black  and  galvanized  for  temperatures  up  to  450  deg. 
-In.  and  smaller  proved  to  300  Ib.  per  sq.  in  by  hydraulic  pressure 
-In.  and  larger  proved  to  500  Ib.  per  sq.  in.  by  hydraulic  pressure 


Nominal 
diameter 

Actual 
outside 
diameter 

Actual 
inside 
diameter 

Inside 
circum- 
ference 

Outside 
circum- 
ference 

Length  of 
pipe  per 

SCJ.  ft. 

of  inside 
surface 

Length  of 
pipe  per 
sq.  ft.  of 
outside 
surface 

Inside 
area 

Outside 
area 

Length  of 
pipe  con- 
taining one 
cubic  foot 

Weight 
per  ft. 

In. 

In. 

In. 

In. 

In. 

Ft. 

Ft. 

In. 

In. 

Ft. 

Lb. 

y* 

0.405 

0.270 

0.818 

1  272 

14.15 

9.44 

0.0572 

0.129 

2500. 

0.243 

x 

0.54 

0.364 

1.144 

1.696 

10.50 

7.075 

0.1041 

0.229 

1385. 

0.422 

H 

0.675 

0.494 

1.552 

2.121 

7.67 

5.657 

0.1916 

0.358 

751.5 

0.561 

H 

0.84 

0.623 

1.957 

2.652 

6.13 

4.502 

0.3048 

0.554 

472.4 

0.845 

H 

1.05 

0.824 

2.589 

3.299 

4.635 

3.637 

0.5333 

0.866 

270. 

1.126 

l 

1.315 

1.048 

3.292 

4.134 

3.679 

2.903 

0.8627 

1.357 

166.9 

1.670 

\% 

1.66 

1.380 

4.335 

5.215 

2.768 

2.301 

1.496 

2.164 

96.25 

2.258 

\Vi 

1.90 

1.611 

5.061 

5.969 

2.371 

2.01 

2.038 

2.835 

70.65 

2.694 

2 

2.375 

2.067 

6.494 

7.461 

1.848 

1.611 

3.355 

4.430 

42.36 

3.600 

zy2 

2.875 

2.468 

7.754 

9.032 

1.547 

1.328 

4.783 

6.491 

30.11 

5.773 

3 

3.50 

3.067 

9.636 

10.996 

1.245 

1.091 

7.388 

9.621 

19.49 

7.547 

3H 

4.00 

3.548 

11.146 

12.566 

1.077 

0.955 

9.887 

12.566 

14.56 

9.055 

4 

4.50 

4.026 

12.648 

14.137 

0.949 

0.849 

12.730 

15.901 

11.31 

10.66 

4K 

5.00 

4.508 

14.153 

15.708 

0.848 

0.765 

15.939 

19.635 

9.03 

12.34 

5 

5.563 

5.045 

15.849 

17.475 

0.757 

0.629 

19.990 

24.299 

7.20 

14.50 

6 

6.625 

6.065 

19:054 

20.813 

0.63 

0.577 

28.889 

34.471 

4.98 

18.767 

7 

7.625 

7.023 

22.063 

23.954 

0.544 

0.505 

38.737 

45.663 

3.72 

23.27 

8 

8.625 

7.982 

25.076 

27.096 

0.478 

0.444 

50.039 

58.426 

2.88 

28.177 

9 

9.625 

9.001 

28.277 

30.433 

0.425 

0.394 

63.633 

73.715 

2  26 

33.70 

10 

10.75 

10.019 

31.475 

33.772 

0.381 

0.355 

78.838 

90.762 

1.80 

40.06 

11 

12.00 

11.25 

35.343 

37.699 

0.340 

0.318 

98.942 

113.097 

1.455 

45.95 

12 

12.75 

12.000 

38.264 

40.840 

0.313 

0.293 

116.535 

132.732 

1.235 

48.98 

14 

14.00 

13.25 

41.268 

43.982 

0.290 

0.273 

134.582 

153.938 

1.069 

53.92 

15 

15.00 

14.25 

44.271 

47.124 

0.271 

0.254 

155.968 

176.715 

.923 

57.89 

16 

16.00 

15.25 

47.274 

50.265 

0.254 

0.238 

177.867 

201.062 

.809 

61.77 

18 

18.00 

17.25 

53.281 

56.548 

0.225 

0.212 

225.907 

254.469 

.638 

69.66 

20 

20.00 

19.25 

59.288 

62.832 

0  202 

0.191 

279.720 

314,160 

.515 

77.57 

*\Valworth  Manufacturing  Company 

Table  28-3.     Standard  Pipe  Threads  (Briggs  Formula) 


I  Perfect  Bottom 

K-Flit  Top  ind  Bottom->-<      but— *  perfect  Thread  Top  and  Bottom 
-FJaLlflp 


Taper  of  pipe  end  =  %-in.  per  ft.  =  T*-in.  per  in. 
Depth  of  thread  (D)  =  0.8  x  no.  of  threads  per  in 


^ „      T.hr"d*. »*2  Threads**— f- (0.8  DH.+4.8)  i£- 

Ctiamter  in  Die       ' 


t*.     • 

A  8.1s 

§  U<S.9 

*OT3  C 

S"S.S 

C8        — 

1  «>'°.s 

e  •35 

"•S-S 

•  B« 

^•"'~ 

flj| 

4* 

sll 

11] 

^  c  jj'£ 

iiji 

.^JI 

i\i 

o  "'a 

•  5  a 

11  1| 

o 

*"*  w**" 

** 

**  w"** 

H 

27 

0.393 

0.331 

0.19 

3 

8 

3.441 

3.241 

0.95 

18 

0.522 

0.433 

0.29 

3J^ 

8 

3.938 

3.738 

1.00 

a4 

18 

0.656 

0.568 

0.30 

4 

8 

4.434 

4.234 

1.05 

1A 

14 

0.815 

0.701 

0.39 

41-2 

8 

4.931 

4.731 

1.10 

14 

1.025 

0.911 

0.40 

5 

8 

5.490 

5.290 

1.16 

I  " 

11H 

1.283 

1  .  141 

0.51 

6 

8 

6.516 

6.346 

1.26 

1M 

\\y-i 

1.626 

1.488 

0.54 

i 

8 

7.540 

7.340 

1.36 

1J^ 

\\y% 

1.866 

1.728 

0.55 

8 

8 

8.534 

8.334 

1.46 

2 

\\y> 

2.339 

2.201 

0  .  58 

9 

8 

9.527 

9.327 

1.57 

2H 

8 

2.819 

2.619 

0  89 

10 

8 

10.645 

10.445 

1  68 

316 


Table  28-4.     Dimensions  of  Black  and  Galvanized  Wrought-Iron  Pipe 


Six* 

Extra   strong 

Double   extra    strong 

Diameters 

Thickness 

Weight 
per  foot 
Plain  ends 

Diameters 

Thickness 

Weight 
per  foot 
PUin  ends 

External 

Internal 

External 

Internal 

y» 

.  Ilir, 

.21.-, 

.095 

.314 

X 

.540 

.302 

.119 

.535 

M 

.675 

.423 

.126 

.738 

1A 

.ato 

.546 

.147 

1.087 

.840 

.252 

.294 

1.714 

H 

1  030 

.742 

.154 

1.473 

1.050 

.434 

.308 

2.440 

l 

1.315 

.957 

.179 

2.171 

1.315 

.599 

.358 

3.659 

IK 

1.660 

1.278 

.191 

2.996 

1.660 

.896 

.382 

5.214 

l*A 

1.900             1.500 

.200 

3.631 

1.900 

1.100 

.400 

6.408 

2 

2.375             1  939 

.218 

5.022 

2.375 

1.503 

.436 

9.029 

2^              2.875             2.323 

.276 

7.661 

2.875 

1.771 

.552 

13.695 

3 

3.500             2.900           .300 

10.252 

3.500 

2.300 

.600 

18.583 

3H 

4.000             3.364           .318 

12.505 

1.  000 

2.728 

.636 

22.850 

4 

4.500             3.826           .337 

14.983 

4.500 

3.152 

.674 

27.541 

4H 

5.000             4.290           .355 

17.611 

5.000 

3.580 

.710 

32.530 

5 

5.563 

4.813           .375 

20.778 

5.563 

4.063 

.750 

38.552 

6 

6.625 

5.761            .432 

28.573 

6.625 

4.897 

.864 

53.160 

7 

7.625 

6.625           .500 

38.018 

7.625 

5.875 

.875 

63.079 

8 

8.625             7.625           .500 

43.388 

8.625 

6.875 

.875 

72.424 

9 

9.625 

8.625 

.500 

48.728 

10 

10.750 

9.750 

.500 

54.735 

11 

11.750 

10.750           .500 

60.075 

12 

12.750 

11.750           .500 

65.415 

13 

14.000 

13.000           .500 

72.091 

14 

15.000 

14.000 

.500 

77.431 

15 

16.000 

15.000 

.  :>0(l 

82.771 

Table  28-5.     Dimensions  of  Standard   Boiler  Tubes* 


Length  of  tube 

Diameter 

Circumference 

Transverse  area 

per  square  foot 

Nominal 

'    M  .__,     „  

of 

weight 

thickness          no. 

external 

internal 

per 

External 

Internal 

B.  Wire 

External 

Internal 

External    Internal 

Metal 

surface 

surface 

foot 

Gauge 

Square 

Square 

Square 

Inches 

Inches 

Inches 

Inches 

Inches 

inches 

inches 

inches 

Feet 

Feet 

Pounds 

1« 

1.560 

.095 

13 

.-,.198 

4.901 

2.405 

1.911 

.494 

2.182 

2.448 

1.679 

2 

1.810 

.095 

13 

6.283 

5.686 

3.142 

2.573 

.569 

1.909 

2.110 

1.932 

2K 

2.060 

.095 

13 

7.069 

6.472 

3.976 

3.333 

.643 

1.697 

1.854 

2.186 

VA 

2.282 

.109 

12 

7.8.-.I 

7.169 

4.909 

4.090 

.819 

.527 

1.674 

2.783 

2Ji 

2.532 

.109 

12 

8.639 

7.955 

5.940 

5.036 

.904 

.388 

1.508 

3.074 

3 

2.782 

.109 

12 

9.425 

8.740 

7.069 

6.079 

.990 

.273 

1.373 

3.365 

3K 

3.010 

.120 

11 

10.210 

9.456 

8.296 

7.116 

1.180 

.175 

1.269 

4.011 

3H 

3.260 

.120 

11 

10.996 

10.242 

9.621 

8.347 

1.274 

.091 

1.171 

4.331 

3*A 

3.510 

.120 

11 

11.781 

11.027 

11.015 

9.677 

1.368 

.018 

1.088 

4.652 

4 

3.732 

.131 

10 

12.566 

11.724 

12.566 

10.939 

1.627 

.954 

1.023 

5.532 

4H 

4.232 

.134 

10 

14.137 

13.295 

15.904 

14.066 

1.838 

.818 

.902 

6.248 

5 

1.7(11 

.148 

9 

15.708 

14.778 

19.635 

17.379 

2.256 

.763 

.812 

7.669 

•Crane  Co. 


Table  28-6.     Surface  Factors  for  Pipes 


Size 
of  pipe 

Factors  for 
reducing  lin- 
eal ft.  to 
sq.  ft. 

Factors  for 
reducing  sq. 
ft.  lo 
lineal  ft. 

Size 
of  pipe 

Factors  for 
reducing  lin- 
eal ft.  to 
sq.  ft. 

Factor  for 
reducing  sq. 
ft.  to 
lineal  ft. 

Size 
of  pipe 

Factors  for 
reducing  lin- 
eal ft.  to 
sq.  ft. 

Factors  for 
reducing  sq. 
ft.  to 
lineal  ft. 

,* 
ft 

2 

2H 

.27 

.33 
.43 
.50 
.62 
.75 

3.64 
2.90 
2.30 
2  01 
1.61 
1  33 

3 

3*A 
4 
4^ 
5 
6 

.92 
1.05 
1.19 
1.31 
1.61 
1.75 

1.09 
.96 
.85 
.76 
.63 
.58 

7 
8 
9 
10 
12 

•2  .00 
2.23 
2.50 
2.85 
3.33 

.50 
.44 
.40 
.36 
.30 

317 


Table  28-7.    Expansion  of  Wrought-Iron  Pipe  on  the  Application  of  Heat* 


Temp,  air  when 
pipe  is  fitted 
Deg.  fahr. 

160 

Increase  in  length  in  inches  per  foot  when  heated  to 
180                     200                     212                     220                     228 

240 

274 

0 
32 
50 

70 

.0128 
.0102 
.0088 
.0072 

.  0144 
.0118 
.0101 
.0088 

.016 
.0134 
.012 
.0104 

.017 
.0144 
.013 
.0114 

.0176 
.015 
.0136 
.012 

.0182 
.0157 
.0142 
.0126 

.0192 
.0166 
.0152 
.0136 

.0219 
.0194 
.0179 
.0163 

Coefficient:^ 

.0000067 

per  deg.  lahr. 

*  Holland 

Hivilini:  \l;ti 

HlJll 

Table  28-8.    Heat  Units  Per  Pound  and  Weight  Per  Cubic  Foot  of  Water 
Between  32  Deg.  Fahr.  and  340  Deg.  Fahr.f 


1  Temperature,  1 
degrees  fahr. 

Heat  units 
per  pound 

Weight  per 
cubic  foot 

1  Temperature, 
degrees  fahr. 

Heat  units 
per  pound 

Weight  per 
cubic  foot 

Temperature, 
degrees  fahr. 

Heat  units 
per  pound 

jfi 

J5  u 

•n 

i*3 

Temperature, 
degrees  fahr. 

Heat  units 
per  pound 

Weight  per 
cubic  foot 

Temperature, 
degrees  fahr. 

Heat  units 
per  pound 

Weight  per 
cubic  foot 

Temperature, 
degrees  fahr. 

Heat  units 
per  pound 

Weight  per 
cubic  foot 

32 

0.00 

62.42 

70 

38.06 

62.30 

108 

75.95 

61.90 

146 

113.86 

61.2" 

184 

151.8 

60.49 

222 

190. 

59.58 

33 

1.01 

62.42 

71 

39.06 

62.30 

109 

76.9 

61.88 

147 

114.86 

61.25 

185 

152.89 

60.4' 

223 

191. 

59.55 

34 

2.01 

62.42 

72 

40.05 

62.29 

110 

77.94 

61.86 

148 

115.86 

61.24 

186 

153.89 

60.45 

224 

192.1 

59.53 

35 

3.02 

62.43 

7; 

41.05 

62.28 

111 

78.94 

61.85 

149 

116.86 

61.22 

187 

154.90 

60.42 

225 

193.1 

59.50 

36 

4.03 

62.43 

74 

42.05 

62.27 

112 

79.93 

61.83 

150 

117.86 

61.20 

188 

155.90 

60.40 

226 

194.1 

59.48 

37 

5.04 

62.43 

75 

43.05 

62.26 

113 

80.93 

61.82 

151 

118.86 

61.18 

189 

156.90 

60.38 

227 

195.2 

59.45 

38 

6.04 

62.43 

76 

44.04 

62.26 

114 

81.93 

61.80 

152 

119.86 

61.16 

190 

157.91 

60.36 

228 

196.2 

59.42 

39 

7.05 

62.43 

77 

45.04 

62.25 

115 

82.92 

61.79 

153 

120.86 

61.14 

191 

158.91 

60.33 

229 

197.2 

59.40 

40 

8.05 

62.43 

78 

46.04 

62.24 

116 

83.92 

61.77 

154 

121.86 

61.12 

192 

159.91 

60.31 

230 

198.2 

59.37 

41 

9.05 

62.43 

79 

47.04 

62.23 

117 

84.92 

61.75 

155 

122.86 

61.10 

193 

160.91 

60.29 

231 

199.2 

59.34 

42 

10.06 

62.43 

80 

48.03 

62.22 

118 

85.92 

61.74 

156 

123.86 

61.08 

194 

161.92 

60.27 

232 

200.2 

59.32 

43 

11.06 

62.43 

81 

49.03 

62.21 

119 

86.91 

61.72 

157 

124.86 

61.06 

195 

162.92 

60.24 

233 

201.2 

59.29 

44 

12.06 

62.43 

82 

50.03 

62.20 

120 

87.91 

61.71 

158 

125.86 

61.04 

196 

163.92 

60.22 

234 

202.2 

59.27 

45 

13.07 

62.42 

83 

51.02 

62.19 

121 

88.91 

61.69 

159 

126.86 

61.02 

197 

164.93 

60.19 

235 

203.2 

59.24 

46 

14.07 

62.42 

84 

52.02 

62.18 

122 

89.91 

61.68 

160 

127.86 

61.00 

198 

165.93 

60.17 

236 

204.2 

59.21 

47 

15.07 

62.42 

85 

53.02 

62.17 

123 

90.90 

61.66 

161 

128.86 

60.98 

199 

166.94 

60.15 

237 

205.3 

59.19 

48 

16.07 

62.42 

86 

54.01 

62.16 

124 

91.90 

61.65 

162 

129.86 

60.96 

200 

167.94 

60.12 

238 

206.3 

59.16 

49 

17.08 

62.42 

87 

55.01 

62.15 

125 

92.90 

61.63 

163 

130.86 

60.94 

201 

168.94 

60.10 

239 

207.3 

59.14 

50 

18.08 

62.42 

88 

56.01 

62.14 

126 

93.90 

61.61 

164 

131.86 

60.92 

202 

169.95 

60.07 

240 

208.3 

59.11 

51 

19.08 

62.41 

89 

57.00 

62.13 

127 

94.89 

61.59 

165 

132.86 

60.90 

203 

170.95 

60.05 

241 

'09.3 

59.08 

52 

20.08 

62.41 

91 

58.00 

62.12 

128 

95.89 

61.58 

166 

33.86 

60.88 

201 

171.96 

60.02 

242 

10.3 

59.05 

53 

21.08 

62.41 

91 

59.00 

62.11 

129 

96.89 

61.56 

167 

34.86 

60.86 

205 

172.96 

60.00 

243 

211.4 

9.03 

54 

22.08 

62.40 

92 

60.00 

62.09 

130 

97.89 

61.55 

168 

35.86 

60.84 

206 

173.97 

59.98 

244 

212.4 

9.00 

55 

23.08 

62.40 

93 

60.99 

62.08 

131 

98.89 

61.53 

169 

36.86 

60.82 

207 

174.97 

39.95 

245 

213.4 

8.97 

56 

24.08 

62.39 

94 

61.99 

62.07 

132 

99.88 

61.52 

170 

37.87 

60.80 

208 

175.98 

59.93 

246 

214.4 

8.94 

57 

25.08 

62.39 

95 

62.99 

62.06 

133 

100.88 

61.50 

171 

38.87 

60.78 

209 

176.98 

59.90 

247 

215.4 

8.91 

58 

26.08 

62.38 

96 

63.98 

62.05 

134 

101.88 

61.49 

172 

39.87 

60.76 

210 

177.99 

59.88 

248 

216.4 

8.89 

59 

27.08 

62.37 

97 

64.98 

62.04 

135 

102.88 

61.47 

173 

40.87 

60.73 

211 

178.99 

9.85 

249 

217.4 

8.86 

60 

28.08 

62.37 

98 

65.98 

62.03 

136 

103.88 

1.45 

174 

41.87 

60.71 

212 

180.00 

9.83 

250 

218.5 

8.83 

61 

29.08 

62.36 

99 

66.97 

62.02 

137 

104.87 

1.43 

175 

42.87 

60.69 

213 

181.0 

9.80 

260 

228.6 

8.55 

62 

30.08 

62.36 

100 

67.97 

62.00 

138 

105.87 

1.41 

176 

143.87 

60.67 

214 

182.0 

9.78 

270 

238.8 

8.26 

63 

31.07 

62.35 

101 

68.97 

61.99 

139 

06.87 

1.40 

177 

L44.88 

60.65 

215 

183.0 

9.75 

280 

249.0 

7.96 

64 

32.07 

62.35 

102 

59.96 

1.98 

140 

07.87 

1.38 

178 

145.88 

50.62 

216 

184.0 

9.73 

290 

259.3 

7.65 

65 

33.07 

2.34 

103 

0.96 

1.97 

141 

08.87 

1.36 

179 

146.88 

0.60 

217 

L85.0 

9.70 

300 

269.6 

7.33 

66 

34.07 

2.33 

104 

1.96 

1.95 

142 

09.87 

1.34 

180 

147.88 

0.58 

218 

186.1 

9.68 

310 

279.9 

7.00 

67 

35.07 

2.33 

105 

2.95 

1.94 

143 

10.87 

1.33 

181 

L48.88 

0.56 

219 

187.1 

9.65 

320 

290.2 

6.66 

68 

36.07 

2.32 

106 

3.95 

1.93 

144 

11.87 

1.31 

182 

149.89 

0.53 

220 

L88.1 

9.63 

330 

!00.6 

6.30 

69 

37.06 

2.31 

107 

4.95 

1.91 

145 

12.86 

1.29 

183 

150.89 

0.51 

221 

189.  1 

9.60 

340 

ill.O 

5.94 

t  Steam.  Babcock  &  W  ilcox  Co. 


318 


Table  28-9.     Dimensions  of  Cast-Iron  Screwed  Fittings* 

.X 


Size,  inches 


Standard 

A  B 

Inches  Inches 


Extra  heavy 
A  B 

Inches         Inches 


Standard  and  extra  heavy 

C  D  E  F 

Inches     Inches     Inches     Inches 


•A. 


3 
S] 

4 


5 
6 

7 

8 

9 

10 

12 


a 

» 


ift 


2% 


7ft 
»j| 


4H 
5A 
6 


3  Itt 

3H          2J4 

4H          2ft 
5H          3  * 

•  ;1  -  4 

5H 


013 

4}^ 
5A 


HH 


20 


i: 


16?i 


5H 


4J4 


NOTE — The  above  dimensions  are  subject  to  a  slight  variation 

Table  28-10.     45-Degree  Offset  Connections 


*  Crane  Co. 


Pipe 
size 


Centre 
to 

Cf  ntre 
A 


9 


Centre 
to 

face 
B 


1ft 


Face  to 

face  of 

45's 

C 


1* 

H 

^ 


Offset 
D 


Pipe 
size 


IH 

2 


Centre 

to 
centre 

A 


10 


Centre 

to 

face 
B 


I* 

18 

2A 


2 


Face  to 

face  of 

4S's 

C 


Offset 
D 


2H 

m 

3A 


NOTE:  The  Offset  D  i»  « 


l  to  Uic  distance  A  -=-  1.414 


319 


Table  28-11.     Rules  for  Standard  Weight  Flanged  Fittings 
American  1915  Standard,  125-lb.  working  pressure 
Shell  thickness  in  inches 


Size  fitting, 
inches 

Shell 
thickness 

Size  fitting, 
inches 

Shell 
thickness 

Size  fitting, 
inches 

Shell 
thickness 

o 

A 

5 

M 

12 

% 

2H 
3 

A 
1A 

6 

7 

A 
H 

14 
15 

i 

Wi 

ft 

8 

H 

16 

H 

4 

X 

9 

H 

18 

VA 

y 

10 

It                20 

l* 

1.  Standard  reducing  elbows  carry  same  dimensions  center-to-face  as  regular  elbows 
of  largest  straight  size. 

2.  Standard  tees,  crosses  and  laterals,  reducing  on  run  only,  carry  same  dimensions 
face-to-face  as  largest  straight  size. 

3.  Where  long-turn  fittings  are  specified,  it  has  reference  only  to  elbows  which  are  made 
in  two  center-to-face  dimensions  and  to  be  known  as  elbows  and  long-turn  elbows, 
the  latter  being  used  only  when  so  specified. 

4.  All  standard  weight  fittings  must  be  guaranteed  for  125-lb.  working  pressure,  and 
each  must  have  mark  cast  on  indicating  maker  and  guaranteed  working  steam  pressure. 

5.  Standard  weight  fittings  and  flanges  to  be  plain  faced,  and  bolt  holes  to  be  y%  in. 
larger  in  diameter  than  bolts;  bolt  holes  to  straddle  center  lines. 

6.  Size  of  all  fittings  scheduled  indicates  inside  diameter  of  ports. 

7.  Square  head  bolts  with  hexagonal  nuts  are  generally  recommended  for  use. 

8.  Double-branch  elbows,  side-outlet  elbows  and  side-outlet  tees,  whether  straight  or 
reducing,  carry  same  dimensions  center-to-face  and  face-to-face  as  regular  tees  and  elbows. 

9.  Bull-head  tees  or  tees  increasing  on  outlet,  will  have  same  center-to-face  and  face- 
to-face  dimensions  as  a  straight  fitting  of  the  size  of  the  outlet. 

10.  Tees,  crosses  and  laterals  16-in.  and  smaller,  reducing  on  the  outlet,  use  the  same 
dimensions  as  straight  sizes  of  the  larger  port.      (Continued  on  next  page) 


Table  28-12.     Standard  Flanges  and  Bolts 


1915  Standard,  125-lb.  working  pressure 


Pipe 


Size 
P 


1 

IX 


Flange 


Diam. 
D 


10 

11 


Thick- 
ness 
T 


A 
N 

H 
3A 
H 
H 

tt 


Bolts 


No. 


Size 
Diam. 


Bolt  Holes 


Bolt 
circle 
B.C. 


ION 


Size 
Diam. 


* 

N 


K 


Pipe 


Size 
P 


8 

9 

10 

12 

14 
15 
16 
18 

20 
22 
24 
26 

28 
30 
32 
34 

36 
38 
40 


Flange 


Diam. 
D 


15 
16 
19 

21 

22^ 


25 

211A 


32 

34^ 

36^ 


41  % 

43M 

46 


Thick- 

ness 

T 


IN 
IN 
1A 


IN 
1A 
ift 

1H 

m 


2A 
2A 


Bolts 


No. 


8 
12 
12 
12 

12 
16 
16 
16 

20 
20 
20 
24 

28 
28 
28 
32 

32 
32 
36 


Size 
Diam. 


% 
i/. 


Bolt  Holes 


Bolt 
circle 
B.  C. 


17 

1«N 
20 


22M 

25 

27M 


34 
36 
38^ 


42?i 

47M 


Size 
Diam. 


iH 


IN 

IN 

IN 

IN 


320 


Sizes  18-in.  and  larger,  reducing  on  the  outlet,  are  made  in  two  lengths,  depending  on 
the  size  of  the  outlet,  as  given  in  the  table  of  dimensions. 

11.  For  fittings  reducing  on  the  run  only,  a  long-body  pattern  will  be  used.     Y's  are 
special  and  made  to  suit  connections.     Double-branch  elbows  are  not  made  reducing  on 
the  run. 

12.  Steel  flanges,  fittings  and  valves  are  recommended  for  superheated  steam. 

13.  If  flanged  fittings  for  lower  working  pressure  than  125  Ib.  are  made,  they  shall 
conform  in  all  dimensions,  except  thickness  of  shell,  to  this  standard  and  shall  have  the 
guaranteed  working  pressure  cast  on  each  fitting.     Flanges  for  these  fittings  must  be  stand- 
ard dimensions. 


Table  28-13.    Standard  Flanged  Reducing  Laterals 
1915  Standard,  125-lb.  Working  Pressure 


.1 

'Ti^  t 

W&  I 

f^ 

2 

H^bX        .li 

Ij      \l,/a                         l?r 

i—  N<S/ 

Reducing  lateral                             Reducing-on-run                     Reducing-on-run  and 

lateral                                   branch  lateral 

Size 

Dimensions,  inches 

Flanges 

Run  K                 Branch  b                     L                         M                         N                         O 

Diam.             Thickness 

1 

_            _ 

_                         _ 

4                          A 

l]4              \%  or  less              8                       6l/£                   \y±                   6 

4          VA          y2 

\y%          \y±  ' 

9                     7 

2                      7 

2                 2      ' 

10J4                   8 

21A                 8 

6             y» 

3  2             3  2  ' 

12                       9 
13                    10 

4           2Y2            9y2            i              H 
3              10               iy2 

3/^             3^4  * 

'    "              14^                11) 

3                    11 

4                 4      ' 

15                    12 

3                    12 

4V£             4^  "    "              15H                12H                  3                    12y2                 Wi.                  fi 

5                 5      ' 

17                    13^                  3*4                13^                10 

6                 6      ' 

is              uy2            3y2           ulA           11              i 

7                 7      ' 

20H                16J 

/i                 4                    16, 

4             12H             1A 

8                  8       ' 

22                    17J 

i                  4^                17K                13^                1^ 

9                 9      ' 

24                    19} 

414                19 

4.               15                   \^ 

10               10      ' 

25^                20y2                 5  "                20M                16                    1A 

12               12      ' 

30                   24^                  5^                24Ji                19                    1% 

14               14      ' 

33                   27 

6                    27 

21               \ys 

15               15      ' 

34^                28' 

6                    28] 

16               16      ' 

36^                30 

6^                30 

231A                1A 

18                 9      ' 

26                   25 

1                    27^                25"                1A 

18               18  to  10  inc.          39                    32 

7                    32 

25                    1A 

20                10  and 

less              28 

1                    29! 

4                27  i4                If* 

20               20  to  12  inc.          43                    35                     8                    35  "                2l']4                l\i 
10  and  less             29                     28^                     YL                3VA                291A                 \\i 

22               22  to  12  inc.          46                   37^4                 S1A                37^                29^                Itf 
24                12  and  less              32                     311A                     14                W1A                 32                     V/, 

24               24  to  14  inc.          491A                W1A                 9                   401A                32                    VA 

26                12  and 

less             35                    35 

0                    38 

34M                2 

26               26  to  14  inc.          53                    44 

9                    44 

3*1A                2 

28                14  and 

less             37                    37 

0                    40 

WA               2A 

28               28  to  15  inc.          56                   46H                  9J/6                46K                36'H                2A 

30                15  and 

less              39                     39 

0                    42 

38%                2% 

30               30  to  16  inc           59                   49 

10                    49 

38^                2^ 

321 


Table  28-14.     Standard  Flanged  Bull-Head  Reducing  Tees  and  Crosses 
1915  Standard,  125-lb.  Working  Pressure 


Reducing  tee 


Reducing  cross 


Reducing-on-run  tee 


P-A-^A-^                                          ^->r_ 

•—  j  —  >j«—  j  —  > 

^j1         ]'. 

7$lrt~3i:        I-trBffr 

is^ffli 

I    j     17                 ^1j  ICl 

dtC- 

kfi->i                                              Hfr*. 

kn 

Bull-head  tee                                           Reducing-on-run  and 

Reducing-on-run  branch 

Branch  tee  cross 

Size                                                                            Dimensions,  inches 

Flanges 

Run-R                 Branch  b                  A  &  J                  K 

Diam.           Thickness 

j 

4                     A 

\y±            1      or  less               3%               3% 

41^                 y^ 

ll/2            \]4  "                      4                   4 

5                    A 

2                IK  "                       4J^               4^ 

6                    % 

2y2            2       "     "                 5                   5                                                                               7                     11 
2y2  "                       5H               ^V-i           Note  —  A  reduction  in  size  on             iy2                 % 

3^2                                            6                   6               </ie  run   does   not  affect  the             8J4                 \i 

4                3J^  "                       6J^               6y2           dimensions  but 

branch   out-             9 

lets  of  small  size  such  as  are 

ty2                                                                               listed   below  will  reduce  the             9%                 |f 

5                4J/6  "                       iy2               iy2          dimensions  of  fittings  18  in.           10 

65                               8                   8               or  over  in  size 

11                   1 

7                6       "     "                 8H               Sy2 

12H               1A 

8                7       "     "                 9                   9 

13^          \y% 

9                8       "     "               10                 10 

15            iys 

10               9      "    "              11                11 

16                  1A 

12              10       "     "               12                 12 

19                  1M 

14              12       "     "              14                 1-1 

21                   1% 

15                14        "     "                 Ul/2              \\y2             Branch  b 

16             15      "    "              15                15 

23M              1A 

18              18  to  14  inc.           16J/6             W/2           12  or  less 

13           15^           25                   I,*; 

20             20  to  15  inc.           18                18              14  "    " 

14           17               27J^               1H 

22              22  to  16  inc.           20                 20               15  "     " 

14          18              29Y2              1M 

24             24  to  18  inc.          22                22              16  "    " 

15          19              32                  V/s 

26             26  to  20  inc.          23                23              18  "    " 

16          20              34^              2 

28             28  to  20  inc.          24                24              18  "    " 

16          21              36^              2^ 

30             30  to  22  inc.          25                25              20  "    " 

18          23              38M              2ys 

32             32  to  22  inc.          26                26              20  "    " 

18          24              41  H              2% 

34             34  to  24  inc.          27                27              22  "    " 

19          25              43M              2^ 

36              36  to  26  inc.           28                 28               24  "     " 

20          26              46                  2^ 

38              38  to  26  inc.           29                 29               24  "     " 

20           28               48%               2% 

40              40  to  28  inc.           30                 30               26  "     " 

22          29              50%              2y2 

322 


Table  28-15.     Standard  Flanged  Elbows,  Crosses,  Laterals  and  Reducers 
1915  Standard,  125-lb.  Working  Pressure 


Elbow 


Long-turn  elbow 


Reducing  elbow 


4S-deg.  elbow 


Double-branch 
elbow 


Straight  tee 


p. 

1           ' 
1 
1 

r-l 

1 

'  ' 

0 

i  i 

L 

•  = 

c 

j 

i. 

-t«- 

Straight  cross 


Straight  lateral 


Reducer 


Size 
Run-R 

A 

B 

Dimensions, 
C 

inches 
D 

E 

G 

Diam. 

Flange 
Thickness 

1 

3y2 

5 

IK 

7H 

5Ji 

___ 

4 

A 

1/4 

3% 

5^2 

2  * 

8 

6J4 

— 

4J-3 

/"i 

iy2 

4 

6 

2M 

9 

7 

— 

5 

A 

2 

4}/3 

6y2 

2}i 

io}/3 

8 

— 

6 

% 

2*A 

5 

7 

3 

12 

9y2 



7 

tt 

3 

sj/3 

7% 

3 

13 

10 

6 

iy> 

54 

3j/3 

6 

sj/3 

3/^ 

14J/3 

ny2 

6J^ 

ij 

4 

f>Vt 

9 

4 

15 

12 

7 

9  2 

H 

4}"3 

7 

Wi 

4 

15V3 

\2y2 

7J/3 

9M 

ii 

5 

iy2 

*V9ft 

4J^ 

17 

13Ji 

8 

10 

fl 

6 

8 

1  1  /2 

5 

18 

UJ| 

9 

11 

1 

7 

*1A 

12?4 

VA 

20^ 

1  63^2 

10 

12>3 

lA 

8 

9 

14 

51A 

22 

17  v3 

1| 

13H 

l>i 

9 

10 

15/4 

6 

24 

19H 

\iy2 

15 

1V6 

10 

11 

16J/3 

6y2 

25^ 

2oy2 

12 

16 

1A 

12 

12 

19 

iy-t 

30 

i\y2 

14 

19 

1}4 

14 

14 

2iy2 

W-L 

33 

27 

16 

21 

lj^ 

15 

Uy2 

22  % 

8 

34  J/3 

28^ 

17 

22^ 

IN 

16 

15 

24 

8 

36  y2 

30 

18 

23^ 

1  16 

18 

16*A 

26J/3 

81A 

39 

32 

19 

25 

•'•TS 

20 

18 

29 

9J-3 

43 

35 

20 

27^ 

1H 

22 

20 

31  H 

10 

46 

37  H 

22 

29  J/3 

iff 

24 

22 

34 

11 

49J-3 

wy2 

24 

32 

l  V* 

26 

23 

36M 

13 

53 

44 

26 

34J4 

2 

28 

24 

39 

14 

56 

46 

28 

36^ 

2A 

30 

25 

41!/3 

15 

59 

49 

30 

38% 

32 

26 

44 

16 

— 

— 

32 

41  M 

2/4 

34 

1'7 

46^ 

17 

— 

— 

34 

43M 

2& 

36 

28 

49 

18 





36 

46 

2^ 

38 

29 

51J/3 

19 

— 

— 

38 

4834 

2/^ 

40 

30 

54 

20 

— 

— 

40 

50  J4 

2H 

323 


Table  28-16.     Rules  for  Extra-Heavy  Flanged  Fittings 

American  1915  Standard  250-lb.  Working  Pressure 
Shell  thickness  in  inches 


Size  fitting, 
inches 

Shell 
thickness 

Size  fitting, 
inches 

Shell 
thickness 

Size  fitting, 
inches 

Shell 
thickness 

2 

% 

5 

M 

12 

1^8 

3  2 

N 

6 

7 

i 

14 

15 

$ 

31^ 

N 

8 

H 

16 

•*•  16 

4 

« 

9 

i 

18 

1A 

4M 

it 

10 

1* 

20 

1.  Extra  heavy  reducing  elbows  carry  same  dimensions  center-to-face  as  regular  elbows 
of  largest  straight  size. 

2.  Extra  heavy  tees,  crosses  and  laterals,  reducing  on  run  only,  carry  same  dimensions 
face-to-face  as  largest  straight  size. 

3.  Where  long-turn  fittings  are  specified,  it  has  reference  only  to  elbows  which  are  made 
in  two  center-to-face  dimensions  and  to  be  known  as  elbows  and  long-turn  elbows,  the  latter 
being  used  only  when  so  specified. 

4.  Extra  heavy  fittings  must  be  guaranteed  for  250-lb.  working  pressure,  and  each 
fitting  must  have  some  mark  cast  on  it  indicating  the  maker  and  guaranteed  working  steam 
pressure. 

5.  All  extra  heavy  fittings  and  flanges  to  have  a  raised  surface  YS  m-  high  inside  of  bolt 
holes  for  gaskets.     Thickness  of  flanges  and  center-to-face  dimensions  of  fittings  include  this 
raised  surface.     Bolt  holes  to  be  y%  in.  larger  in  diameter  than  bolts.     Bolt  holes  to  straddle 
center  lines.      (Continued  on  next  page.) 


Pipe 

Size 
P 


3 

3} 
4 


Table  28-17.     Extra-Heavy  Pipe  Flanges  and  Bolts 
1915  Standard,  250-lb.  Working  Pressure 


Flange 


Diam. 
D 


9 
10 


Thick- 

ness 

T 


tt 


Bolts 


No. 


4 
4 
4 
4 

4 
8 
8 
8 

8 
8 

12 
12 


Size 


Bolt  holes 


Bolt 
circle 
B.  C. 


Bolt 
hole 


H 

i/a 


Pipe 

Size 
P 


8 
9 

10 
12 

14 
15 
16 
18 

20 
22 
24 
26 

28 
30 
32 
34 

36 
38 

40 


Flange 


Bolts 


Diam. 


15 

16 

ny2 


23 

2'iy2 
2$y2 
2sy2 

3oy2 

33 
36 

38M 

40  M 
43 

45M 


50 

52M 


Thick- 

ness 

T 


l% 

2 

2A 


No. 


12 
12 

16 

20 
20 
20 
24 

24 

24 
24 
28 

28 
28 
28 
28 

32 
32 
36 


Size 


lYs. 


Bolt  holes 


Bolt 
circle 
B.  C. 


13 
14 


22^ 
24^ 

27 
29 
:S2 


37 

39M 


43^ 

46 
48 


Bolt 
hole 


1 

iys 


IK 


324 


6.  Sizt-  of  all  fittings  scheduled  indicates  inside  diameter  of  ports. 

7.  Square  head  bolts  with  hexagonal  nuts  are  generally  recommended  for  use. 

8.  Double  branch  elbows,  side  outlet  elbows  and  side  outlet  tees,  whether  straight  or 
reducing  sizes,  carry  same  dimensions  center-to-face  and  face-to-face  as  regular  tees  and 
elbows. 

9.  Bull-head  tees  or  tees  increasing  on  outlet,  will  have  same  center-to-face  and  face-to- 
face  dimensions  as  a  straight  fitting  of  the  size  of  the  outlet. 

10.  Tees,  crosses  and  laterals  16-in.  and  smaller,  reducing  on  the  outlet,  use  the  same 
dimensions  as  straight  size  of  the  larger  port.     Sizes  18  in.  and  larger,  reducing  on  the  outlet, 
are  made  in  two  lengths,  depending  on  the  size  of  the  outlet  as  given  in  the  table  of  dimen- 
sions. 

11.  For  fittings  reducing  on  the  run  only  a  long  body  pattern  will  be  used.     Y's  are 
special  and  made  to  suit  connections.     Double  branch  elbows  are  not  made  reducing  on  the 
run. 

12.  Steel  flanges,  fittings  and  valves  are  recommended  for  superheated  steam. 

Table  28-18.     Extra-Heavy  Flanged  Reducing  Laterals 

1915  Standard,  250-lb.  Working  Pressure 


Reducing  lateral 


Reducing-on-run 
lateral 


Reducing  on-run  and 
Branch  lateral 


Run-R 

Size 
Branch  b 

Dimensions,  inches 
L                           M 

N 

0 

Flanges 
Ilium.              Thickness 

1 

1J4  and  less 

~A 

~ 

~A 

- 

5  2 

H 

IN 

1  Yi     "       " 

11 

8^1 

~^A 

8j| 

6 

i 

2 

<>                   *4               It 

UN 

9 

VA 

9 

6J^ 

2y2 

2N     "      " 

13 

10^  ' 

2H 

wy2 

7N 

l 

3 

3         "       " 

14 

11 

3 

11 

8/4 

1J^ 

3N 

3J-£     "      " 

15J/2 

izy2 

3 

i2y2 

9 

1A 

4 

4         ••       •• 

16N 

ny2 

3 

\VA 

10 

4N 

4N    "     " 

18 

uy2 

3N 

uy2 

10V$ 

1A 

5 

5        "      " 

18/^ 

15 

3y2 

15 

11 

IN 

6 

7 

6 

§H 

17^ 
19 

4 

VA 

19  2 

14  2 

1A 

8 

8        "      " 

25N 

2oy2 

5 

2oy2 

15 

IN 

9 

9        »      » 

27  N 

22^ 

5 

22y2 

16}4 

IN 

10 

10        "      " 

29^ 

24 

5^ 

24 

17  Vi 

IN 

12 

12        "      " 

33  H 

2VA 

6 

2iy2 

20  >i 

2 

14 

14        "      " 

37J^ 

31 

6H 

31 

23 

2N 

15 

15        "      " 

39y2 

33 

VA 

33 

24  J^ 

16 

16        "      " 

42 

34  1^ 

34  y2 

25  J^ 

9/4 

18 

9 

34 

31 

3  2 

32K 

28 

2N 

18 

16  to  10  inc. 

45^ 

3iy2 

8 

37^ 

28 

2N 

20 

10  and  less 

37 

34 

3 

36 

30  y2 

20 

18  to  12  inc. 

49 

40  y2 

8}^ 

wlA 

30  J^ 

2y2 

22 

10  iind  less 

40 

37 

3 

39 

33 

2>A 

22 

20  to  12  inc. 

53 

43^ 

91A 

4sy2 

33 

2N 

24 

12  and  lij~s 

44 

41 

3 

43 

36 

24 

22  to  1  1  inc. 

•"'"  '  i 

47  1A 

10 

47  H 

36 

2N 

325 


Table  28-19.     Extra-Heavy  Flanged  Bull-Head  Reducing  Tees  and  Crosses 
1915  Standard,  250-lb.  Working  Pressure 


kbT 

Reducing  tee 


r^rii      l±= 


| 

nl 


Reducing  cross 


Reducing-on-run  tee 


r-t- 


Bull-head  tee 


Reducing-on-run  and  branch  tee 


Reducing-on-run  and  branch  cross 


Run-R 

Size 
Branch  b 

J 

Dimensions, 
K 

inches 

Diam. 

Flanges 
Thickness 

1 

_ 

_ 

_ 

4y2 

H 

1)4 

1      or  less 

4/4 

4  Vi 

5 

\Yz 

1/4  "     " 

4J^ 

4>  Vo 

6 

it 

2 

1M  "     ' 

5 

5 

61A 

H 

21A 

2       "     " 

51A 

5Ji 

ly^ 

1 

3 

2]/2    "      " 

6 

6 

8)4 

IJ's 

4 

3      ''    " 

7 

7 

Note  —  A  reduction  in  size  on 

9 

10 

IS 

the  run   does  not  affect   tfie 

4H 

4      "     - 

7j* 

71^ 

dimensions  but  branch  out- 

10H 

Ire 

5 

VA  "  " 

8 

8 

lets  of  smaller  size  than  those 

11 

l/'i 

6 

5       "    " 

V<i 

8J-£ 

listed  below  will  reduce  the 

\iy% 

1A 

7 

6      "    " 

9 

9 

dimensions  of  fittings  18  in. 

14 

or  over  in  size 

8 

7       "     " 

10 

10 

15 

l/^ 

9 

8       "     " 

10}^ 

10J^ 

16)4 

1J4 

10 

9      «    •• 

ny2 

11^ 

17/^ 

l^i 

12 

10      "    " 

13 

13 

20M 

2 

14 

12       "     " 

15 

15 

23 

21A 

15 

14       "     " 

15H 

15J^ 

Branch                   J                 K 

24  y2 

2A 

16 

15       "     " 

16  ^ 

16^5 

25)-^ 

2)4 

18 

18  to  14  inc. 

18 

18 

12  or  less             14             17 

28 

2^ 

20 

20  to  15  inc. 

191A 

"^ 

14         "               15)^         18^i 

so  y2 

2)^ 

22 

22  to  16  inc. 

2oy2 

15         "               \6l/2         20 

33 

2^i 

24 

24  to  18  inc. 

22  « 

22)| 

16         "               17             2V/2 

36 

2M 

26 

26  to  20  inc. 

24 

24 

18        "              19            23 

38)4 

2il 

28 

28  to  20  inc. 

26 

26 

18        "              19            24 

40  M 

2i| 

30 

30  to  22  inc. 

27  y2 

27  i/S 

20         "               20H         25H 

43 

3 

32 

32  to  22  inc. 

29 

29 

20         "              20y2         26y2 

45)^ 

3H 

34 

34  to  24  inc. 

30)3 

30H 

22    '     "              22             28 

47)| 

3)4 

36 

36  to  26  inc. 

32H 

32)^ 

21  "    "              23)^        29M 

50 

33^ 

38 

38  to  26  inc. 

34 

3t 

24  "    "              23}4        30^ 

5214 

3  A 

40 

40  to  28  inc. 

35^ 

35  H 

26  "    "              25            31  Yi 

54)^ 

3n 

326 


Table  28-20.     Extra-Heavy  Flanged  Elbows,  Crosses,  Laterals  and  Reducers 
1915  Standard,  2.">0-U>.  Working  Pressure 


Elbow 


Long-turn  elbow 


Reducing  elbow 


Double-branch 
elbow 


I         ft          t\t         ft         > 

TTTJS^ 

<  A  >r*   ••   ^                                            j— 

Hi!                   r%             i—0  H 

LU               ^      •    /^s_/                               n 

•    ~r     ?        HTpf 

Hr                      QT/                     <^X^ 

^3<      1  *,/</     a 



1- 

(  j|  i  it 

i  i      ififa/        " 

LJ 

PI      '   i 

^                                UR-,  X: 

F*a                    4   A   T 

Straight  tee                                      Straight  cross                                      Straight  lateral                                       Reducer 

Size                                                                   Dimensions,  inches                                                                        Flange 

Run-R                   A                         B                         C                        D                        E                       G                  Diam. 

Thickness 

1                   4                    5                    2                    8J/6              6Ji                                 4V6 
1)4               4%                5H                2^                9)i              7X                                 5 

I 

| 

!)/£               4J-£                6                   5 

!%              11                  8^                                 6 

t* 

25                   6J^                3                  \\V-i              9                                     61A 

Jj 

2H               5)3                7                    : 

IJ4              13                10V4                                 7J4 

1 

36                    7%                3j/i              11                11   "              6                  8H 

1) 

1 

31^               6J/6                8}/£                4                  15)i            12V^              f>lA              9 
4                   7                    9                    41A              16Ji            13H              7                10 

IS 

4H              7}i               9^               •! 

154         is           1414         ly*        \oy2 

If 

i 

5                   8                  10J4     .          5  "              18J/6            15                  8                11                  13A 

6                   8J/2              HJ^                J 

\y,         2iy2        niA         9           \2>A 

i  j 

., 

7                   9                  12%                6                  23Ji            19                10                14                  IJi 

8                 10                  14                    6                  25^            20J^            11                15                  \Y» 

9                IQ^A             15J4               ' 

>y2          2iy2         22y2         114         16^4 

i* 

I 

10            uy2         uy2           i            29y2        24           12           \~iy-i          W% 

12                 13                  19                    8                  33H            27J/6            14                20J^ 

2 

U                 13                  2\Y2                I 

>H              37H            31                16                23 

2) 

i 

15                 15J^              22%                9                  39J/6  •          33                17                24J^              2A 

16                 16^              24                    9Y2              42                34^            18                25  J^              2X 

18                 18                  26^              10                  45^            37^            19                28                  2% 

20                 19  Ji              29                  1( 

)V£              49                40U            20                30J4 

2) 

i 

22                  20y2               31  ^               11                   53                 43)i             22                 33 

2H 

24                 22y2              34                  12                  57)^            47^            24                36 

2J 

i 

26                 21                  36^              13                                                        26                38J4              2H 

28                 26                  39                  14                                                        28                40%              2ft 

30                  127  1,               41V6               15                                                           30                 43 

3 

32                 29                  44                  16                                                        32                 IV, 

3} 

i 

34                 30^              46J^              17                                                        34                47J4              3X 

36                 32J^              49                  18                                                        36                50                  3^ 

38                 :u                  51  1A              19                                                        38                52  X              3  A 

40                 35H              54                  20                                                       40                54}^              3T\ 

327 


Table  28-21.     Properties  of  Saturated  Steam 

Reproduced  by  permission  from  Marks  and  Davis  Steam   Tables  and  Diagrams.    Copyright,  1909,  by 

Longmans,  Green  &  Co. 


Pressure,  Ib. 
absolute 

Temperature, 
deg.  fahr. 

Specific  volume, 
cu.  ft.  per  Ib. 

Heat  of  the 
liquid,  B.t.u. 

Latent  heat  of 
evap.,  B.t.u. 

Total  heat  of 
steam,  B.t.u. 

Pressure,  Ib. 
absolute 

1 

101.83 

333.0 

69.8 

1034.6 

1104.4 

1 

2 

126.15 

173.5 

94.0 

1021.0 

1115.0 

2 

3 

141.52 

118.5 

109.-1 

1012.3 

1121.6 

3 

4 

153.01 

90.5 

120.9 

1005.7 

1126.5 

4 

5 

162.28 

73.33 

130.1 

1000.3 

1130.5 

5 

6 

170.06 

61.89 

137.9 

995.8 

1133.7 

6 

7 

176.85 

53.56 

144.7 

991.8 

1136.5 

7 

8 

182.86 

47.27 

150.8 

988.2 

1139.0 

8 

9 

188.27 

42.36 

156.2 

985.0 

1141.1 

9 

10 

193.22 

38.38 

161.1 

982.0 

1143.1 

10 

11 

197.75 

35.10 

165.7 

979.2 

1144.9 

11 

12 

201.96 

32.36 

169.9 

976.6 

1146.5 

12 

13 

205.87 

30.03 

173.8 

974.2 

1148.0 

13 

14 

209.55 

28.02 

177.5 

971.9 

1149.4 

14 

14  7 

212.0 

26.79 

180.0 

970.4 

1150.4 

14.7 

15 

213.0 

26.27 

181.0 

969.7 

1150.7 

15 

16 

216.3 

24.79 

184.4 

967.6 

1152.0 

16 

17 

219.4 

23.38 

187.5 

965.6 

1153.1 

17 

18 

222.4 

22.16 

190.5 

963.7 

1154.2 

18 

19 

225.2 

21.07 

193.4 

961.8 

1155.2 

19 

20 

228.0 

20.08 

196.1 

960.0 

1156.2 

20 

22 

233.1 

18.37 

201.3 

956.7 

1158.0 

22 

24 

237.8 

16  93 

206.1 

953.5 

1159.6 

24 

26 

242.2 

15.72 

210.6 

950.6 

1161.2 

26 

28 

246.4 

14.67 

214.8 

947.8 

1162.6 

28 

30 

250.3 

13.74 

218.8 

945.1 

1163.9 

30 

32 

254.1 

12.93 

222.6 

942.5 

1165.1 

32 

34 

257.6 

12.22 

226.2 

940.1 

1166.3 

34 

36 

261.0 

11.58 

229.6 

937.7 

1167.3 

36 

38 

264.2 

11.01 

232.9 

935.5 

1168.4 

38 

40 

267.3 

10.49 

236.1 

933.3 

1169.4 

40 

42 

270.2 

10.02 

239.1 

931.2 

1170.3 

42 

44 

273.1 

9.59 

242.0 

929.2 

1171.2 

44 

46 

275.8 

9.20 

244.8 

927.2 

1172.0 

46 

48 

278.5 

8.84 

247.5 

925.3 

1172.8 

48 

50 

281.0 

8.51 

250.1 

923.5 

1173.6 

50 

52 

283.5 

8.20 

252.6 

921.7 

1174.3 

52 

54 

285.9 

7.91 

255.1 

919.9 

1175.0 

54 

56 

288.2 

7.65 

257.5 

918.2 

1175.7 

56 

58 

290.5 

7.40 

259.8 

916.5 

1176.4 

58 

60 

292.7 

7.17 

262.1 

914.9 

1177.0 

60 

62 

294.9 

6.95 

264.3 

913.3 

1177.6 

62 

64 

297.0 

6.75 

266.4 

911.8 

1178.2 

64 

66 

299.0 

6.56 

268.5 

910.2 

1178.8 

66 

68 

301.0 

6.38 

270.6 

908.7 

1179.3 

68 

70 

302.9 

6.20 

272.6 

907.2 

1179.8 

70 

72 

304.8 

6.04 

274.5 

905.8 

1180.4 

72 

74 

306.7 

5.89 

276.5 

904.4 

1180.9 

74 

76 

308.5 

5.74 

278.3 

903.0 

1181.4 

76 

78 

310.3 

5.60 

280.2 

901.7 

1181.8 

78 

80 

312.0 

5.47 

282.0 

900.3 

1182.3 

80 

328 


Table  28-21.    Properties  of  Saturated  Steam — Continued 


Pressure,  Ib. 
absolute 

Temperature, 
deg.  fahr. 

Specific  volume, 
cu.  ft.  per  Ib. 

Heat  of  tbe 
liquid,  b.t.u. 

Latent  heat  of 
evap.,  b.t.u. 

Total  heat  of 
steam,  b.t.u. 

Pressure,  Ib. 
absolute 

82 

313.8 

5.34 

283.8 

899.0 

1182.8 

82 

84 

315.4 

5.22 

285.5 

897.7 

1183.2 

84 

86 

317.1 

5.10 

287.2 

896.4 

1183.6 

86 

88 

318.7 

5.00 

288.9 

895.2 

1184.0 

88 

90 

320.3 

4.89 

290.5 

893.9 

1184.4 

90 

92 

321.8 

4.79 

292.1 

892.7 

1184.8 

92 

94 

323  .4 

4.69 

293.7 

891.5 

1185.2 

94 

96 

324.9 

4.60 

295.3 

890.3 

1185.6 

96 

98 

326.4 

4.51 

296.8 

889.2 

1186.0 

98 

100 

327.8 

4.429 

298.3 

888.0 

1186.3 

100 

105 

331.4 

4.230 

302.0 

885.2 

1187.2 

105 

110 

334.8 

4.047 

305.5 

882.5 

1188.0 

110 

115 

338.1 

3.880 

309.0 

879.8 

1188.8 

115 

120 

341.3 

3.726 

312.3 

877.2 

1189.6 

120 

125 

344.4 

3.583 

315.5 

874.7 

1190.3 

125 

130 

347.4 

3.452 

318.6 

872.3 

1191.0 

130 

135 

350.3 

3.331 

321.7 

869.9 

1191.6 

135 

140 

353.1 

3.219 

324.6 

867.6 

1192.2 

140 

145 

355.8 

3.112 

327.4 

865.4 

1192.8 

145 

150 

358.5 

3.012 

330.2 

863.2 

1193.4 

150 

155 

361.0 

2.920 

332.9 

861.0 

1194.0 

155 

160 

363.6 

2.834 

335.6 

858.8 

1194.5 

160 

165 

366.0 

2.753 

338.2 

856.8 

1195.0 

165 

170 

368.5 

2.675 

340.7 

854.7 

1195.4 

170 

175 

370.8 

2.602 

343.2 

852.7 

1195.9 

175 

180 

373.1 

2.533 

345.6 

850.8 

1196.4 

180 

185 

375.4 

2.468 

348.0 

848.8 

1196.8 

185 

190 

377.6 

2.406 

350.4 

846.9 

1197.3 

190 

195 

379.8 

2.346 

352.7 

845.0 

1197.7 

195 

200 

381.9 

2  290 

354.9 

843.2 

1198.1 

200 

205 

384.0 

2.237 

357.1 

841.4 

1198.5 

205 

210 

386.0 

2.187 

359.2 

839.6 

1198.8 

210 

215 

388.0 

2.138 

361.4 

837.9 

1199.2 

215 

220 

389.9 

2.091 

363.4 

836.2 

1199.6 

220 

225 

391.9 

2.046 

365.5 

834.4 

1199.9 

225 

230 

393.8 

2.004 

367.5 

832.8 

1200.2 

230 

235 

395.6 

1  964 

369.4 

831.1 

1200.6 

235 

240 

397.4 

1  924 

371.4 

829.5 

1200.9 

240 

245 

399.3 

1.887 

373.3 

827.9 

1201.2 

245 

250 

401.1 

1.850 

375.2 

826.3 

1201.5 

250 

Table  28-22.    Indicated  Horsepower  of  an  Engine 

A  =  area  of  the  piston  in  square  inches.  P  =  mean  effective  pressure  of  the  steam  on  the  piston. 
Hi.  per  sq.  in.  L  =  length  of  stroke  in  ft.  N  =  numb<r  of  working  strokes  per  niin.=  2  X  r.  p.  m.  for 
double-acting  cylinder. 

PLAN 

Then   i.hp.  =  — 

33,000 

The  mean  pressure  in  the  cylinder  of  a  non-condensing  engine  when  cutting  off  at 

%  stroke  =  boiler  pressure  multiplied  by  .597  %  stroke  =  boiler  pressure  multiplied  by  .919 

"  .670  %  "  =  "  "  .937 

"  .743  %  "  =  "  "  "  .966 

V-t                                                              '    .847  ya      "       =  "  "    .992 

329 


Table  28-23.    Dimensions  of  Horizontal  Return  Tubular  Boilers* 
Corresponding  to  Am.  Soc.  M.  E.  Standards 


Horse 
power 

t 

Heat- 
ing 
sur- 
face 
Sq.  ft. 

Shell 

Tubes 

THICKNESS  OF  SHELLS  AND  HEADS 

Diameter  of 
nozzle,  in. 

Diameter  of 
feed  pipe,  in. 

Diameter  of 
blow-off,  in. 

125-Lb. 
working  pressure 

150-Lb. 
working  pressure 

Dia. 
In. 

Lgth 
Feet 

No. 

+ 
+ 

Dia. 
In. 

Lgth 
Feet 

Shell 
In. 

Heads 
In. 

Long 
joint 

SheU 
In. 

Hds 
In. 

Long 
joint 

31 

370 

42 

12 

34 

3 

12 

A 

3A 

Double  Butt. 

ti 

A 

Triple  Butt. 

4 

1 

2 

36 

430 

42 

11 

34 

3 

14 

A 

3A 

Double  Butt. 

H 

A 

Triple  Butt. 

4 

1 

2 

39 

470 

48 

12 

44 

3 

12 

M 

4 

Double  Butt. 

M 

4 

Triple  Butt. 

4 

1 

0 

36 

430 

48 

12 

34 

3Ji 

12 

H 

4 

Double  Butt. 

% 

4 

Triple  Butt. 

4 

1 

2 

30 

360 

48 

12 

24 

4 

12 

H 

4 

Double  Butt. 

3A 

1A 

Triple  Butt. 

4 

1 

2 

45 

540 

48 

11 

44 

3 

14 

M 

4 

Double  Butt. 

% 

1A 

Triple  Butt. 

4 

1 

42 

500 

48 

14 

34 

34 

11 

H 

4 

Double  Butt. 

X 

1A 

Triple  Butt. 

4 

1 

35 

420 

48 

14 

24 

4 

14 

& 

4 

Double  Butt. 

H 

4 

Triple  Butt. 

4 

1 

52 

620 

48 

16 

44 

3 

16 

tt 

4 

Double  Butt. 

3A 

4 

Triple  Butt. 

4 

1 

48 

570 

48 

16 

34 

34 

16 

ii 

4 

Double  Butt. 

% 

4 

Triple  Butt. 

4 

1 

40 

480 

48 

16 

24 

4 

16 

M 

4 

Double  Butt. 

3A 

4 

Triple  Butt. 

4 

1 

47 

560 

54 

12 

54 

3 

12 

H 

4 

Triple  Butt. 

A 

A 

Triple  Butt. 

4 

1M 

45 

540 

54 

12 

44 

31A 

12 

% 

4 

Triple  Butt. 

A 

9 

Te 

Triple  Butt. 

4 

1^ 

2 

43 

510 

54 

12 

36 

4 

12 

H 

4 

Triple  Butt. 

A 

9^ 
10 

Triple  Butt. 

4 

i& 

2 

55 

660 

54 

14 

54 

3 

14 

3A 

4 

Triple  Butt. 

A 

A 

Triple  Butt. 

4 

1J4 

2 

53 

630 

54 

11 

44 

34 

14 

*A 

4 

Triple  Butt. 

A 

A 

Triple  Butt. 

4 

llA 

2 

50 

600 

54 

14 

36 

4 

14 

H 

1A 

Triple  Butt. 

A 

9 
T6 

Triple  Butt. 

4 

VA 

••> 

63 

750 

54 

16 

54 

3 

16 

3A 

Yi 

Triple  Butt. 

A 

A 

Triple  Butt. 

4 

VA 

2 

60 

720 

54 

16 

44 

34 

16 

3A 

4 

Triple  Butt. 

A 

A 

Triple  Butt. 

4 

ilA 

2 

58 

700 

54 

16 

36 

4 

16 

3A 

4 

Triple  Butt. 

7 

T6 

A 

Triple  Butt. 

4 

1M 

2 

85 

1021 

60 

16 

76 

3 

16 

H 

9 
TS 

Quad  Butt. 

29 
64 

9 
T6 

Quad  Butt. 

5 

14 

24 

73 

872 

60 

16 

54 

34 

16 

H 

A 

Quad  Butt. 

H 

A 

Quad  Butt. 

5 

14 

24 

68 

822 

60 

16 

44 

4 

16 

3A 

A 

Quad  Butt. 

29 
6^ 

9 
TS 

Quad  Butt. 

5 

14 

24 

96 

1147 

60 

18 

76 

3 

18 

H 

A 

Quad  Butt. 

29 
64 

A 

Quad  Butt. 

5 

14 

24 

82 

980 

60 

18 

54 

34 

18 

3A 

9 
T6 

Quad  Butt. 

H 

9 

TT 

Quad  Butt. 

5 

14 

24 

77 

924 

60 

18 

44 

4 

18 

H 

A 

Quad  Butt. 

H 

A 

Quad  Butt. 

5 

14 

24 

111 

1338 

66 

16 

102 

3 

16 

A 

M 

8uad  Butt. 

4 

% 

Quad  Butt. 

6 

2 

24 

95 

1132 

66 

16 

72 

34 

16 

A 

6A 

uad  Butt. 

1A 

H 

Quad  Butt. 

6 

2 

24 

83 

993 

66 

16 

54 

4 

16 

7 
T6 

H 

Quad  Butt. 

1A 

H 

Quad  Butt. 

6 

2 

24 

125 

1504 

66 

18 

102 

3 

18 

A 

5A 

Quad  Butt. 

1A 

5A 

Quad  Butt. 

6 

2 

24 

106 

1272 

66 

18 

72 

34 

18 

A 

^ 

euad  Butt. 

4 

5A 

Quad  Butt. 

6 

2 

24 

93 

1116 

66 

18 

54 

4 

18 

A 

H 

uad  Butt. 

4 

H 

Quad  Butt. 

6 

2 

24 

136 

1632 

72 

16 

126 

3 

16 

N 

Quad  Butt. 

H 

H 

Quad  Butt. 

6 

9 

24 

123 

1474 

72 

16 

96 

34 

16 

M 

Quad  Butt. 

M 

H 

Quad  Butt. 

6 

o 

24 

107 

1289 

72 

16 

72 

4 

16 

H 

5A 

Quad  Butt. 

M 

5A 

Quad  Butt. 

6 

2 

24 

153 

1834 

72 

18 

126 

3 

18 

§1 

5A 

Quad  Butt. 

M 

H 

Quad  Butt. 

6 

2 

24 

138 

1657 

72 

18 

96 

34 

18 

u 

5A 

Quad  Butt. 

H 

H 

Quad  Butt. 

6 

o 

24 

120 

1448 

72 

18 

72 

4 

18 

H 

5A 

Quad  Butt. 

« 

5A 

Quad  Butt. 

6 

2 

24 

169 

2037 

72 

20 

126 

3 

20 

j| 

*A 

Quad  Butt. 

H 

Ys 

Quad  Butt. 

6 

*> 

24 

153 

1839 

72 

20 

96 

34 

20 

K 

% 

Quad  Butt. 

H 

H 

Quad  Butt. 

6 

2 

24 

134 

1608 

72 

20 

72 

4 

20 

n 

5A 

Quad  Butt. 

17 
32 

SA 

Quad  Butt. 

6 

o 

24 

178 

2139 

78 

18 

148 

3 

18 

1A 

H 

Quad  Butt. 

ft 

5A 

Quad  Butt. 

7 

2 

24 

167 

2001 

78 

18 

118 

34 

18 

1A 

H 

Quad  Butt. 

5A 

Quad  Butt. 

7 

9 

24 

145 

1745 

78 

18 

88 

4 

18 

4 

5A 

Quad  Butt. 

if 

H 

Quad  Butt. 

7 

2 

24 

197 

2375 

78 

20 

148 

3 

20 

1A 

y* 

Quad  Butt. 

if 

H 

Quad  Butt. 

7 

o 

24 

186 

2232 

78 

20 

118 

34 

20 

4 

*A 

Quad  Butt. 

1  <t 
TT7 

SA 

Quad  Butt. 

7 

2 

24 

161 

1938 

78 

20 

88 

4 

20 

1A 

H 

Quad  Butt. 

if 

H 

Quad  Butt. 

7 

o 

24 

*Coatesville  Boiler  Works,  Philadelphia,  Pa. 

tFor  heating  boilers,  a  boiler  horsepower  is  assumed  in  this  table  to  be  equivalent  to  12  sq.  ft.  of  heating  surface 
JA  boiler  of  48-in.  diameter  and  larger  has  a  manhole  in  the  front  head  below  the  tubes  in  addition  to  the  regular  manhole 
in  the  upper  part  of  the  shell  or  front  head 

330 


Table  28-24.     Properties  of  Air 


Temper- 
ature, 
deg. 

Vol. 

°f  ^             Cubic              Weight 
air                                        per  cu. 

with                                         ft.  of 
unity                                       dry 

Elastic 
force 
of 
vapor  in 

in       if 

Cubic 
feet 
of 
vapor 

B.t.u.  ab- 
sorbed per 
cu.  ft.  of  air 
per  deg.  fahr. 

Co.  ft.  of 
air  raised  1 
deg.  fahr.  by  1 
b.t.u. 

fahr.            .132               '"•."•                  air 

deg.                                         in  Ib. 

mer-                Ib.  o" 
cury                  wntftr 

Dry 

Sat. 

Dry 

Sat. 

fabr. 

air 

air 

air 

air 

Zero 

0.935 

11.58 

0.0864 

0  044          .  .    . 

ft  ft9ftsfi       n  fton^i 

48.5 

48.7 

12 

0.960 

1T87 

o!0842 

0  074                           f>  09001       n  n9nnfi 

50.1 

50.0 

22 

0  980 

12  1  1 

0  0824 

0  118 

0.01961        0.01963 

51.  1 

51  0 

32 

liooo 

12!  40 

OI0807 

0.181         3289 

0^01921        0.  01924 

52!  o 

si.  a 

42 

1.020 

12.64 

0.0791 

0.267 

2252             0.01882 

0.01884 

53.2 

52.8 

52 

1.041 

12  88 

0.0776 

0.388 

1595 

0.01847 

0.01848 

54.0 

53.8 

60 

1  .  057 

12.39 

0.0764 

0.522 

1227 

0.01818 

0.01822 

55.0 

54.6 

62 

1.061 

13.13         0.0761 

0.556 

1135 

0.01811 

0.01812 

55.2 

54.7 

70 

1.0T8 

13.34 

0.0750 

0.754 

882 

0.01777 

0.01794 

56.3 

55.5 

72 

1.082          13.39          0.0747 

0.785 

819             0.01767 

0.01790 

56.5 

55.8 

82 

1.102          13.64          0.0733 

1  .  092           600 

0.01744 

0.01770 

57.2 

56.5 

92 

1.122          13.90 

0.0720 

1.501           444 

0.01710 

0.01751 

58.5 

57.1 

100 

1.139 

13  95 

0  0710 

1.929 

356 

0.01690 

0.01735 

59.1 

57.8 

102 

1.143 

14.14 

0.0707 

2.036 

331 

0.01682 

0.01731 

59.5 

57.8 

112 

1.163 

14.40 

0  0694 

2.731 

253 

0.01651 

0.01711 

60.6 

58.5 

122 

1  184 

14.65 

0.0682 

3.621 

194 

0.01623 

0.01691 

61.7 

59.1 

132 

1.204 

14.90 

0.0671 

4.752 

151 

0.01596 

0.01670 

62.5 

59.9 

142 

1.224 

15.15 

0.0660 

6.165 

118 

0.01571 

0.01652 

63.7 

60.6 

152 

1.245 

15.40 

0.0649 

7.930 

93.3 

0.01544 

0.01631 

65.0 

61.5 

162 

1.265 

15.65 

0.0638 

10.099 

74.5 

0.01518 

0.01616 

66.2 

62.4 

172 

1.285 

15.90 

0.0628 

12.758 

59.2 

0.01491 

0.01598 

67.1 

63.3 

182 

1.306 

16.17 

0.0618 

15.960 

48.6 

0.01471 

0.01580 

68.0 

64.2 

192 

1.326 

16.42 

0.0609 

19.828 

39  8 

0.01449 

68.9 

202 

1.347 

16.67 

0.0600 

21.450 

32.7 

O.OU26 

69.5 

212 

1.367 

16.92 

0  0591 

29.921 

27.1 

0.01406 

71.4 



Table  28-25.     Volume  and  Weight  of  Air  at  Atmospheric  Pressure  at 
Temperatures  Between  212  and  850  Deg.  Fahr. 


Temperature, 
degrees 
fahrenheit 

Volume  of 
one  pound      Weight  one 
ln               cubic  foot 
cubic  feet        in  Pounds 

Temperature 
degrees 
fahrenheit 

Volume  of 
one  pound 
in 
cubic  feet 

Weight  one 
cubic  foot 
in  pounds 

Temperature, 
degrees 
fahrenheit 

Volume  of 
one  pound 
in 
cubic  feet 

Weight  one 
cubic  foot 
in  pounds 

212 
220 
230 
240 

16.925         .059084 
17.127          .058388 
17.379          .057541 
17.631          .056718 

320 
340 
360 
380 

19.647 
20.151 
20.655 
21.159 

.  050898 
.019625 
.048411 
.047261 

550 
575 
600 
650 

25.444 
26.074 
26.704 
27.964 

.039302 
.038352 
.037448 
.035760 

250 
260 
270 
280 

17.883         .055919 
18.135          .055112 
18.387          .054386 
18.639          .053651 

400 
12:, 
ISO 
175 

21.663 
'2'2  293 
22  923 
23.5:.  I 

.046162 
.04t8:>7 
0  13624 
.0  12156 

700 
750 
800 
850 

29.224 
30.484 
31.744 
33.004 

.034219 
.032804 
.031502 
.030299 

290 
300 

18.891          .052935 
19.113         .052238 

500 
525 

21.184 
21  8H 

.041350 
.040300 

331 


Table  28-26.     Weight  of  Water  at  Temperatures  Used  in  Physical 

Calculations 


Temperature,  Degrees  Fahrenheit 

Weight  per 
cubic  foot, 
pounds 

Weight  per 
cubic  inch, 
pounds 

At  32  degrees  or  freezing  point  at  sea  level        

62  418 

0  03612 

At  39.2  degrees  or  point  of  maximum  density  

62  427 

0  03613 

At  62  degrees  or  standard  temperature  

62  355 

0  03608 

At  212  degrees  or  boiling  point  at  sea  level    

59  846 

0  03469 

Table  28-27.    Volume  and  Weight  of  Distilled  Water  at  Various 

Temperatures* 


Tem- 
per- 
ature, 
deg. 
fahr. 

Relative 
volume 
water  at  39.2 
deg.=  l 

Weight 
inlb. 
per 
cubic 
foot 

Tem- 
per- 
ature, 
deg. 
fahr. 

Relative 
volume, 
water  at  39.2 
deg.  =  l 

Weight 
inlb. 
per 
cubic 
foot 

Tem- 
per- 
ature, 
deg. 
fahr. 

Relative 
volume, 
water  at  39.2 
deg.  =  l 

Weight 
inlb. 
per 
cubic 
foot 

Tem- 
per- 
ature, 
deg. 

fahr. 

Relative 
volume, 
water  at 
39.2  deg. 
=  1 

Weight 
inlb. 
per 
cubic 
foot 

32 

1.000176 

62.42 

160 

1  .  02337 

61.00 

290 

1.0830 

57.65 

430 

1.197 

52.2 

39.2 

1  .  000000 

62.43 

170 

1  .  02682 

60.80 

300 

1.0890 

57.33 

440 

1.208 

51.7 

40 

1.000004 

62.43 

180 

1.03047 

60.58 

310 

1.0953 

57.00 

450 

1.220 

51.2 

50 

1.00027 

62.42 

190 

1.03431 

60.36 

320 

1.1019 

56.66 

460 

1.232 

50.7 

60 

1  .  00096 

62.37 

200 

1  .  03835 

60.12 

330 

1  .  1088 

56.30 

470 

1.244 

50.2 

70 

1  .  00201 

62.30 

210 

1  .  04256 

59.88 

310 

1.1160 

55.94 

480 

1.256 

49.7 

80 

1  .  00338 

62  22 

212 

1.04343 

59.83 

350 

1  .  1235 

55.57 

490 

1.269 

49.2 

90 

1  .  00504 

62.11 

220 

1.0469 

59.63 

360 

1.1313 

55.18 

500 

1.283 

48.7 

100 

1.00698 

62.00 

230 

1.0515 

59.37 

370 

1  .  1396 

54.78 

510 

1.297 

48.1 

110 

1.00915 

61.86 

240 

1.0562 

59.11 

380 

1  .  1483 

54.36 

520 

1.312 

47.6 

120 

1.01157 

61.71 

250 

1.0611 

58.83 

390 

1.1573 

53.94 

530 

1.329 

47.0 

130 

1.01420 

61.55 

260 

1.0662 

58.55 

400 

1.167 

53.5 

540 

1.35 

46.3 

140 

1  .  01705 

61.38 

270 

1.0715 

58.26 

410 

1.177 

53.0 

550 

1.37 

45.6 

150 

1.02011 

61.20 

280 

1.0771 

57.96 

420 

1.187 

52.6 

560 

1.39 

44.9 

*  Marks  and  Davis. 


Table  28-28.     Boiling  Point  of  Water  at  Various  Altitudes 


Boiling  point, 
degrees 

fahrenheit 

Altitude  above 
sea  level, 
feet 

Atmospheric 
pressure, 
pounds  per 
square  inch 

Barometer 
reduced 
to  32  degrees, 
inches 

Boiling  point, 
degrees 
fahrenheit 

Altitude  above 
sea  level, 
feet 

Atmospheric 
pressure, 
pounds  per 
square  inch 

Barometer 
reduced 
to  32  degrees, 
inches 

184 

15221 

8.20 

16.70 

199 

6843 

11.29 

22.99 

185 

14649 

8.38 

17.06 

200 

6304 

11.52 

23.47 

186 

14075 

8.57 

17.45 

201 

5764 

11.76 

23.95 

187 

13498 

8.76 

17.83 

202 

5225 

12.01 

24.45 

188 

12934 

8.95 

18.22 

203 

4697 

12.26 

24.  9b 

189 

12367 

9.14 

18.61 

204 

4169 

12.51 

25.48 

190 

11799 

9.34 

19.02 

205 

3642 

12.77 

26.00 

191 

11243 

9.54 

19.43 

206 

3115 

13.03 

26.53 

192 

10685 

9.74 

19.85 

207 

'     2589 

13.30 

27.08 

193 

10127 

9.95 

20.27 

208 

2063 

13.57 

27.63 

194 

9579 

10.17 

20.71 

209 

1539 

13.85 

28.19 

195 

9031 

10.39 

21.15 

210 

1025 

14.13 

28.76 

196 

8481 

10.61 

21.60 

211 

512 

14.41 

29.33 

197 

7932 

10.83 

22.05 

212 

Sea  Level 

14.70 

29.92 

198 

7381 

11.06 

22.52 

332 


Table  28-29.    Pressures  Corresponding  to  Given  Heads  of  Water  in  Feet 

Water  at  maximum  density.  Temperature,  39.2  deg.  fahr. 
h  =  head  in  feet.     P  =  pressure  in  Ib.  per  sq.  inch  =  .443  h 


h 

p 

h 

P 

h 

P 

h 

P 

h 

P 

h 

P 

h 

P 

1 

.433 

16 

6.928 

31 

13.42 

46 

19.92 

61 

26.41 

76 

32.91 

91 

39.40 

2 

.866 

17 

7.361 

32 

13.86 

47 

20.35 

62 

26.85 

77 

33.34 

92 

:',<).!!  I 

3 

1.299 

18 

7.794 

33 

14.29 

48 

20.78 

63 

27.28 

78 

33.77 

93 

40.27 

4 

1.732 

19 

8.227 

34 

14.72 

49 

21.22 

-  64 

27.71 

79 

34.21 

94 

40.70 

5 

2.165 

20 

8.660 

35 

15.15 

50 

21.65 

65 

28.14 

80 

34.64 

95 

41.13 

6 

2.598 

21 

9.09 

36 

15.59 

51 

22.08 

66 

28.58 

81 

35.07 

96 

41.57 

7 

3.031 

22 

9.53 

37 

16.02 

52 

22  52 

67 

29.01 

82 

35.51 

97 

42.00 

8 

3.464 

23 

9.96 

38 

16.  15 

53 

22^95 

68 

29.44 

83 

35.94 

98 

42.43 

9 

3.897 

24 

10.39 

39 

16.89 

54 

23.38 

69 

29.88 

84 

36.37 

99 

42.87 

10 

4.330 

25 

10.82 

40 

17.32 

55 

23.81 

70 

30.31 

85 

36.80 

100 

43.30 

11 

4.763 

26 

11.26 

41 

17.75 

56 

24.25 

71 

30.74 

86 

37.24 

12 

5.196 

27 

11.69 

42 

18.19 

.  57 

24.68 

72 

31.18 

87 

37.67 

13 

5.629 

28 

12.12 

43 

18.62 

58 

25.11 

73 

31.61 

88 

38.10 

14 

6.062 

29 

12.56 

44 

19.05 

59 

25.55 

74 

32.04 

89 

38.54 

15 

6.495 

30 

12.99 

45 

19.48 

60 

25.98 

75 

32.47 

90 

38.97 

Table  28-30.     Pressure,  in  Ounces  Per  Square  Inch  Corresponding  to 
Various  Heads  of  Water,  in  Inches* 


Head 

Decimal  parts  of  an  inch 

in 

.0                .1                 .2                .3                .4 

.5                .6                .7 

.8                 .9 

inches 

.58 
1.16 

1.73 
2.31 
2  89 

3.47 
4.04 
4.62 
5.20 


.06 

.63 

1.21 

1.79 

2.37 
2.94 

3.52 
4.10 
4.67 
5.26 


.12 

.69 

1.27 

1.85 

2  42 
3.00 

3  58 
4.16 
4.73 
5.31 


.17 

.75 

1.33 

1.91 
2.48 
3.06 

3.64 
4  22 
4!  79 
5.37 


.23 

.81 

1.39 

1.96 
2.54 
3.12 

3.70 
4  28 
4.85 
5.42 


.29 

.87 

1.44 

2.02 
2.60 
3.18 

3.75 
4.33 
4.91 
5.48 


.35 

.93 

1.50 

2.08 
2.66 
3.24 

3.81 
4.39 
4.97 
5.54 


.40 

.98 

1.56 

2.14 

2  72 
Si  29 

3.87 
4.45 
5.03 
5.60 


.46 
1.04 
1.62 

2.19 

2.77 
3.35 

3.92 
4.50 
5.08 
5.66 


.52 
1.09 
1.67 

2.25 
2.83 
3.41 

3.98 
4.56 
5.14 
5.72 


•Suplee's  Mechanical  Engineers'  Reference  Book,  published  by  J.  B.  Lippincott  Co. 


Table  28-31.     Comparison  of  Measures  of  Pressure  and  Weight  f 


1  Ib.  per 
sq.  in. 

1  oz.  per 
sq.  in. 

1  atmos- 
p  h  e  r  e  = 
(14.7  Ib. 
persq.  in.) 


144  Ib.  per  sq.  ft. 

2.0416  in.  mercury  at  62  deg.  fahr. 
2.309  ft.  water  at  62  deg.  fahr. 
27.71  in.  water  at  62  deg.  fahr. 

0.1276  in.  mercury  at  62  deg.  fahr. 
1.732  in.  water  at  62  deg.  fahr. 

21 16.3  Ib.  persq.  ft. 
33.947  ft.  water  at  62  deg.  fahr. 
30  in.  mercury  at  62  deg.  fahr. 
29.922  in.  mercury  at  32  deg.  fahr. 


1  in.  water 
at  62  deg.  = 
fahr. 

1  ft.  water 
at  62  deg.  = 
fahr. 


0.03609  Ib.  or  .5774  oz.  per  sq.  in. 
5.196  Ib.  per  sq.  ft. 

0.433  tb.  per  sq.  in. 
355  Ib.  per  sq.  ft. 


f  0.4 
(6, 


1    in.    mer-      (  0.491  Ib.  or  7.86  oz.  per  sq.  in. 
cury   at  =  {   1.132   ft.    water   at   62   deg.   fahr. 
62 deg. fahr.l   13.58   in.    water  at   62  deg.   fahr. 


tKent's  Mechanical  Engineers'  Pocket  Book 


Table  28-32.     Conversion  of  Mercury  and  Vapor  Pressures 
Inches  of  mercury  to  pounds  per  square  inch 


Tenths 

0 

i 

2 

3 

4 

5 

6 

7 

8 

9 

Inches 

Lb.  Sq.  in. 

Lb.  Sq.  in. 

Lb.  Sq.  in. 

Lb.  Sq.  in. 

Lb.  Sq.  in. 

Lb.  Sq.  in. 

Lb.  Sq.  in. 

Lb.  Sq.  in. 

Lb.  Sq.  in. 

Lb.  Sq.  in. 

0 

0. 

0.49 

0.98 

1.47 

1.96 

2.46 

2.95 

3.44 

3.93 

4.42 

10 

4.91 

5.40 

5.89 

6.39 

6.88 

7.37 

7.86 

8.35 

8.81 

9.33 

20 

9.82 

10.32 

10.81 

11.30 

11.79 

12.28 

12.77 

13.26 

13.75 

14.24 

30 

14.74 

15.2 

15.7 

16.2 

16.7 

17.2 

17.7 

18.2 

18.7 

19.1 

40 

19.6 

20.1 

20.6 

21.1 

21.6 

22.1 

22.6 

23.1 

23.6 

24.1 

50 

24.6 

25.1 

25.5 

26.0 

26.5 

27.0 

27.5 

28.0 

28.5 

29.0 

60 

29.5 

30.0 

30.5 

30.9 

31.4 

31.9 

32.4 

32.9 

33.4 

33.9 

70 

34.4 

34.9 

35.4 

35.9 

36.3 

36.8 

37.3 

37.8 

38.3 

38.8 

80 

39.3 

39.8 

40.3 

40.8 

41.3 

41.8 

42.2 

42.7 

43.2 

43.7 

90 

44.2 

44.7 

45.2 

45.7 

46.2 

46.7 

47.2 

47.6 

48.1 

48.6 

100 

49.1 

49.6 

50.1 

50.6 

51.1 

51.6 

52.1 

52.6 

53.0 

53.5 

Pounds  per  square  inch  to  inches  of  mercury 


Tenths 

0 

l 

2 

3 

4 

s 

6 

7 

g 

9 

Pounds 

In.  Hg. 

In.  Hg. 

In.  Hg. 

In.  Hg. 

In.  Hg. 

In.  Hg. 

In.  Hg. 

In.  Hg. 

In.  Hg. 

In.  Hg. 

0 
10 
20 
30 
40 

0. 

20.352 
40.704 
61.056 
81.408 

2.0352 
22.3872 
42.7392 
63.0912 
83.4432 

4.0704 
24.4224 
44.7744 
65/1264 
85.4784 

6.1056 
26.4576 
46.8096 
67.1616 
87.5136 

8.1408 
28.4928 
48.8448 
69.1968 
89.5488 

10.1760 
30.528 
50.8809 
71.2320 
91.5840 

12.2112 
32.5632 
52.9152 
73.2672 
93.6192 

14.2464 
34.5984 
54.9504 
75.3024 
95.6544 

16.2816 
36.6336 
56.9856 
77.3376 
97.6896 

18.3168 
38.6688 
59.0208 
79.3728 
99.7148 

50 
60 
70 

101.76 
122.11 
142.46 

103.795 
124.145 
144.495 

105.830 
126.180 
146.530 

107.865 
128.215 
148.565 

109.900 
130.250 
150.600 

111.936 
132.286 
152.636 

113.971 
134.321 
154.671 

116.006 
136.356 
156.706 

118.041 
138.391 
158.741 

120.077 
140.427 
160.777 

80 
90 
100 

162.81 
183.16 
203.53 

164.915 
185.195 
205.565 

166.880 
187.230 
207.600 

168.915 
189.265 
209.635 

170.950 
191.300 
211.670 

172.986 
193.336 
213.706 

175.021 
195.371 
215.741 

177.056 
197.406 
217.776 

179.091 
199.441 
219.811 

181.127 
201.476 
221.846 

Table  28-33.     Comparison  of  Measures  of  Pressure 


Name  of  units 

Atmospheres 

On  square 
inch 

Inches 
mercury  at 
32  deg.fahr. 

Feet  of 
water  at 
60  deg.  fahr. 

Millimeters 
of  mercury 
at  32  "fahr. 

Pounds  per 
square  foot 

Kilograms 
per  square 
meter 

Atmosphere  .  . 

1 

14  7 

29  922 

33  94 

760 

2  116 

10  333 

Pounds  per  square  inch  .  . 
In.  mercury  at  32°  fahr.  . 
Feet  of  water  at  60°  fahr.  . 
Millimeters    of     mercurv 
at  32°  fahr  
Pounds  per  square  foot.  . 
Kilograms    per   sq.  meter 

.068,03 
.033,42 
.029,47 

.001,316 
.000,472,6 
.000,096,77 

1. 
.491,3 
.433,2 

.019,34 
.006,947 
.001,423 

2.036 

1. 

.881,8 

.039,37 
.014,13 
.002,895 

2.309 
1.134 
1. 

.044,64 
.016,03 
.003,283 

51.7 

25.398 
22.399 

1. 
.359,2 
.073,55 

143.946 
70.7 
62.35 

2.784 
1. 
.204,8 

702.925 
345.331 
304.565 

13.596 
4.883 
1. 

Table  28-34.     Reasonable  Economic  Performance  of  Stationary  Steam  Plants* 


Type  of  plant 

Central  station 

Mfg.  power  plants 

Heating  plants 

Large 
10,000  kw. 
and  up 

Small 
2000-10,000 
kw. 

Small 
up  to  100 
hp. 

Medium 
100-500 
hp. 

Large 
500-2000 
hp. 

Central 
1000  hp. 
and  up 

Office 
and  public 
bldgs. 

Residence 

Efficiency  of  boiler  and 
Furnace  in  per  cent 

70-76 

68-74 

60-70 

68-72 

68-74 

68-74 

50-70 

50-65 

Coal  per  hour  in  Ih. 

Per  kw-hr. 

Per  1  hp. 

Per  boiler  hp. 

2-3 

2Ji-4 

5-8 

3-5 

2H-t 

3-4 

3-6 

*  L.  P.  Breckenridge.    Lecture  on  Fuel  Conservation 


334 


Table  28-35.    Weight  in  Pounds  of  One  Gallon  of  Water  at  Temperatures  from 

32  Deg.  to  420  Deg.  Fahr. 


Temp. 

Wt. 

Temp. 

Wt. 

Temp. 

Wt. 

Temp. 

Wt. 

32 

8.:iii 

105 

8.279 

185 

8  084 

270 

7.788 

:{.-> 

8.845 

110 

8.270 

190 

8.069 

280 

7.748 

39.2 

8.3151 

115 

8.260 

195 

8.053 

290 

7.707 

40 

8.345 

120 

8.250 

200 

8.037 

300 

7.664 

45 

8  345 

125 

8.239 

205 

8.021 

310 

7.620 

50 

8.343 

130 

8.229 

210 

8.005 

320 

7.575 

:>:> 

8  311 

135 

8.218 

212 

7.998 

330 

7.527 

60 

8  337 

140 

8.206 

215 

7.988 

310 

7.486 

65 

8.333 

148 

8.193 

220 

7.971 

350 

7.429 

70 

8.329 

150 

8.181 

225 

7.954 

360 

7.376 

75 

8.323 

155 

8.168 

230 

7.937 

370 

7.323 

80 

8.317 

160 

8.155 

235 

7.929 

380 

7.267 

85 

8  311 

165 

8.141 

240 

7.920 

390 

7.211 

90 

8.304 

170 

8.127 

245 

7.893 

400 

7.152 

95 

8.296 

175 

8.113 

250 

7.865 

410 

7.085 

100 

8  288 

180 

8.099 

260 

7.828 

420 

7.032 

Table  28-36.    Contents  of  Round  Tanks  in  U.  S.  Gallons,  for  Each  Foot  in  Depth 

To  find  capacity  of  a  tank  of  any  size:    Given  dimensions  of  a  cylinder  in  inches,  to  find  its 
capacity  in  U.  S.  gallons:   Square  the  diameter,  multiply  by  the  length  and  by  .0034 


Diameter 
Ft.        In. 

Gallons, 
1  foot  in 
depth 

Diameter 
Ft.      In. 

Gallons, 
1  foot  in 
depth 

Diameter 
Ft.        In. 

Gallons, 
1  foot  in 
depth 

Diameter 
Ft.        In. 

Gallons, 
1  foot  in 
depth 

1 

0 

5.8735 

7 

0 

287.8032 

15 

0 

1321.5454 

23 

0 

3107.1001 

1 

3 

9.1766 

7 

3 

308.7270 

15 

3 

1365.9634 

23 

3 

3175.0122 

1 

6 

13  2150 

7 

6 

330.3859 

15 

6 

1407.5165 

23 

6 

3243.6595 

1 

9 

17.9870 

7 

9 

352  .  7665 

15 

9 

1457.0032 

23 

9 

3313.0403 

o 

0 

23.4940 

8 

0 

375.9062 

16 

0 

1503.6250 

24 

0 

3383.1563 

2 

3 

29.7340 

8 

3 

399.7666 

16 

3 

1550.9797 

24 

3 

3454.0051 

2 

6 

36.7092 

8 

6 

424.3625 

16 

6 

1599.0696 

24 

6 

3525.5929 

*> 

9 

44.4179 

8 

9 

449.2118 

16 

9 

1647.8930 

24 

9 

3597.9068 

3 

0 

52  8618 

11 

0 

710.6977 

17 

0 

1697.4516 

25 

0 

3670.9596 

3 

3 

62.0386 

11 

3 

743.3686 

17 

3 

1747.7431 

25 

3 

3744.7452 

3 

6 

73.1504 

11 

6 

776.7746 

17 

6 

1798  7698 

25 

6 

3819.2657 

3 

9 

82.5959 

11 

9 

810  9113 

17 

9 

1850  5301 

25 

9 

3894.5203 

4 

0 

93.9754 

12 

0 

848.1890 

18 

0 

1903  0254 

26 

0 

3970.5098 

4 

S 

106.  1200 

12 

3 

881  .  3966 

18 

3 

1956.2537 

26 

3 

4047.2322 

4 

6 

118  9386 

12 

6 

917.7395 

18 

6 

2010.2171 

26 

6 

4124.6898 

4 

9 

132.5209 

12 

9 

954.8159 

18 

9 

2064.9140 

26 

9 

4202.9610 

5 

0 

146.8381 

13 

0 

992.6274 

21 

0 

2590.2290 

27 

0 

4281.8072 

5 

3 

161.8886 

13 

3 

1031.1719 

21 

3 

2652.2532 

27 

3 

4361.4664 

5 

6 

177.6740 

13 

6 

1070.4514 

21 

6 

2715.0413 

27 

6 

4141.8607 

5 

9 

191.1913 

13 

9 

1108.0645 

21 

9 

2778.5486 

27 

9 

4522.9886 

6 

0 

211   4472 

14 

0 

1151.2129 

22 

0 

2842.7910 

28 

0 

4601.8517 

6 

3 

22V    \:':\2 

14 

3 

ll'>2.6940 

22 

3 

2907.7664 

28 

3 

4686.4876 

6 

6 

218    1  :>(.! 

14 

6 

1234  9104 

22 

6 

2973.4889 

28 

6 

4770.7787 

6 

9 

2<>-  <>\22 

14 

9 

1277.8615 

22 

9 

3039.9209 

28 

9 

4854.8434 

335 


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Table  28-38.    Friction  of  Water  in  Pipes 

(living  velocity  in  feet  per  second,  friction  head  in  feet  and  friction  loss  in  pounds  |MT  square  inch 

for  each  100  ft.  of  pipe  discharging  a  given  quantity  of  water  in  gallons 

per  minute     (Weisbach  Formula) 


1 

•o 

"O 

•o 

•o 

«  O 

•o 

•e 

$ 

*!_ 

8 

«•" 

t 

i"~ 

~1 

8 

I'* 

8 

8 

1  '". 

«        1 

O  rr 

1  Gallons  i 

Velocity  i 
per  secon 

Friction  t 
in  feet 

i5 

L° 

Velocity  i 
per  secon 

ll 

£.5 

Friction  1 
Ib.  per  sq 

Velocity  i 
per  secon 

Friction  t 
in  feet 

Ii 

£5 

Velocity  i 
per  secon 

Friction  I 
in  feet 

Ii 

££ 

Velocity  i: 
per  secon 

Friction  t 
in  feet 

Friction  1 
Ib.  per  sq 

H        ll 

I*    £.s 

Friction  1 
Ib.  per.  si 

W'Pipe 

T'Pipe 

lH"Pipe 

IK"  Pipe 

2"  Pipe 

2Mi"Pipe 

5 

3.64 

7.59 

3.3 

2.04 

1.93 

0.84 

1.30 

0.71 

0.31 

0.91 

0.27 

0.12 

0.49 

0.092 

0.04 

0.244 

0.046 

0.02 

10 

7.28 

29.90 

13.0 

4.08 

10.26 

3.16 

2.60 

2.41 

1.05 

1.82 

1.08 

0.47 

0.98 

0.277 

0.12 

0.656 

0.092 

0.04 

1510.92 

66.01 

L'S    7 

6.12 

16.05 

6.98 

3.90 

5.47 

2.38 

2.73 

2.23 

0.97 

1.47 

0.577 

0.25 

0.985 

0.185 

0.08 

2014.56 

115.92 

50.4 

8.16 

28.29 

12.30 

5.20 

9.36 

4.07 

3.64 

3.81 

1.66 

2.04 

0.97 

0.42 

1.315 

0.323 

0.14 

25 

18  W 

180.00 

78.00 

10.20 

43.70 

19.00 

6.50 

14.72 

6.4 

4.55 

5.02 

2.62 

2.60 

1.43 

0  62 

1.645 

O  is:, 

0  21 

n 

12.24 

63.25 

27.50 

7.80 

21.04 

9.15 

5.46 

8.62 

3.75 

3.03 

2.09 

0.91 

1.97     0.693 

0.30 

» 

14.28 

85.10 

37.00 

9.10 

js  .  .-,•_• 

12.4 

6.3711.61 

5.05 

3.54 

2.76 

1.22 

2.29     0.92 

0.40 

« 

16.32 

110.40 

48.00 

0.40 

37.03 

16.10 

7.2814.99 

6.52 

4.05 

3.68 

1.60 

2.62 

1.19 

0.53 

45 

1.70 

46.46 

20.2 

8.1918.74 

8.15 

4.56 

4.60 

1.99 

2.95 

1.49 

0.66 

M 

3.00 

57.27 

24.9 

9.10 

23.00 

10.00 

5.10 

5.61 

2.44 

3.30      1.86 

0.81 

rti 

5.6 

85.50 

37.0 

10.92 

32.'.J.-| 

14.25 

6.12 

8.88 

3.50 

3.95     2.70 

1.17 

70 

8.2 

114.0 

49.3 

12.7444.60 

19.30 

7.1411.09 

4.80 

4.60     3.46 

1.50 

75 

9.5 

129.0 

56.1 

13.6551.52 

22.4 

7.7012.23 

5.32 

4.93     4.14 

1.80 

80 

14.56 

58.45 

25.3 

8.16 

14.55 

6.30 

5.26     4.62 

2.00 

'.HI 

16.3881.50 

35.25 

9.1818.02 

7.80 

5.91      5.96 

2.58 

100 

18.20 

89.70 

39.0 

10.2 

21.75 

9.46 

6.50     7.36 

3.20 

125 

12.8034.27 

14.9 

8.13    11.24 

4.89 

150 

15.3 

48.76 

21.2 

9.80    16.10 

7.00 

IT.', 

11.43  21.75 

9.46 

185 

12.08   24.50 

10.61 

200 

13.06   28.68 

12.47 

3"  Pipe 

3H"  Pipe 

4"  Pip* 

5"  Pipe 

6"  Pipe 

7"  Pipe 

in 

0.448     0.046 

0.02 

It 

0.672 

0.092   O.O4 

0.498 

0.046 

0.02 

I'll 

0.896 

0.138 

0.06 

0.664 

0.069 

0.03 

25 

1.12 

0.231 

0.10 

0.83 

0.092 

0.04 

n 

1.345 

0.30 

0.13 

0.996 

0.138 

0.06 

u 

1.569 

0.393 

0.17 

1.163 

0.208 

O.O9 

40 

1.790 

0.53 

0.23 

1.329 

0.254 

0.11 

1.04 

0.138 

0.06 

4:i 

2.016 

0.647 

0.28 

1.494 

0.323,  0.14 

1.17 

0.1615 

0.07 

• 

2.24 

0.80 

0.35 

1.66 

0.393 

0.17 

1.30 

0.208 

0.09 

>V  1 

2.688 

1.155 

0.50 

1.992 

0.555 

0.24 

1.56 

0.30 

0.13 

0.880.1156 

0.05 

711 

3.136 

1.385 

0.60 

2.334 

0.879 

0.38 

1.82 

0.439 

0.19 

.04 

0.162 

0.07 

75 

3.360 

1.70 

0.75 

2.490 

0.913 

0.395 

1.95 

0.485 

0.21 

.200.174 

0.075 

80 

3.584 

2.08 

0.90 

2.656 

0.948 

0.41 

2.08 

0.580 

0.23 

.280.185 

0.08 

M 

4.032 

2.54 

1.10 

J.'.IXX 

1.247 

0.56 

2.34 

0.60 

0.26 

.44 

0.208 

0.09 

UK 

4.480 

3.01 

1.31 

3.320 

1.478 

0.64 

2.60 

0.763 

0.33 

.600.277 

0.12 

1.14 

0.115 

0.05 

12.-, 

5.60 

4.57 

1.99 

4.15 

2.219 

0.96 

3.25 

1.13 

0.49 

2.000.393 

0.17 

1.42 

0.161 

0.07 

in 

5.80 

6.55 

2.85 

4.98 

3.12 

1.35 

3.80 

1.59 

0.69 

2.400.578 

0.25 

1.71 

0.231 

0.10 

1.20 

0.093 

0.04 

IT.', 

7.92 

8.85 

3.85 

5.81 

4.208 

1.82 

4.45 

2.146 

0.93 

2.8O 

IJ.7x.-i 

0.34 

2.00 

0.302 

0.13 

1.38      0.115 

0.05 

is.', 

8.34 

9.94 

4.30 

6.14 

4.62 

2.00 

4.70 

2  484 

1.075 

2.96 

(l.sl 

0.36 

2.11 

0.36 

0.15€ 

1.55     0.13 

0.056 

2U 

9.04 

11.54 

5.02 

6.64 

5.50 

2.38 

5.1 

2  82 

1.22 

3.200.972 

0.42 

2.28 

0.39 

0.17 

1.70     0.162 

0.07 

25011.28 

17.84 

7.76 

8.30 

8.55 

3.70 

6.4 

4.37 

1.89 

4.001.50 

0.65 

2.80 

0.60 

0.26 

2.10     0.277 

0.12 

.'.,:, 

12.40 

20.09 

8.72 

8.80 

9.60 

4.15 

6.79 

6.45 

2.09 

4.24 

1.69 

0.73 

3.03 

0.70 

0.303 

2.23     0.31 

0.134 

30013.52 

25.76 

11.20 

9.96 

11.63 

5.04 

7.60 

6.15 

2.66 

4.802.15 

0.93 

3.40 

0.85 

0.37 

2.40     0.393 

0.17 

Hot  water  averages  8  Ib.  per  gallon 

Horsepower  required  to  raise  water:  -horsepower  =•  quantity  in  cu.  ft.  per  min.  X  height  of  lift  in  feet  -i-  529.2  -  quantity 
in  gal.  per  min.  Y.  height  of  lift  in  feet  -f-  3958.7 

When  the  temperature  of  water  increases,  the  pressure  of  the  water  vapor  decreases  the  theoretical  lift,  which  at  ISO  deg. 
fahr.  =  25.7  ft.;  at  175  deg.  =  18.5  ft.,  and  at  200  deg.  =  7.2  ft. 


887 


Table  28-39.     Cost  of  Water  at  Stated  Rates  per  1000  Gallons 


Number 

Cost  per  1000  Gallons 

of 
cubic  feet 

S  Cents 

6  Cents 

8  Cents 

10  Cents 

IS  Cents 

20  Cents 

25  Cents 

30  Cent* 

20 

$0.007 

$0.009 

$0.012 

$0.015 

$0.021 

$0. 

030 

$0.037 

$0.045 

40 

0.015 

0.018 

0.024 

0.030 

0.045 

0. 

060 

0.075 

0.090 

60 

0.022 

0.027 

0.036 

0.045 

0.066 

0. 

090 

0.112 

0.135 

80 

0.030 

0.036 

0.048 

0.060 

0.090 

0. 

120 

0.150 

0.180 

100 

0.037 

0.049 

0 

.060 

0.075 

0.111 

0. 

150 

0.187 

0.224 

200 

0.075 

0.090 

0.120 

0.150 

0.225 

0. 

299 

0.374 

0.449 

300 

0.112 

0.135 

0.180 

0.224 

0.336 

0. 

449 

0.561 

0.673 

400 

0.150 

0.180 

0.239 

0.299 

0.450 

0. 

598 

0.748 

0.898 

500 

0.188 

0.224 

0.299 

0.374 

0.564 

0. 

748 

0.935 

1.122 

600 

0.224 

0.269 

0.359 

0.449 

0.448 

0. 

898 

1.122 

1.346 

700 

0.262 

0.314 

0.419 

0.524 

0.786 

1. 

047 

1.309 

1.571 

800 

0.299 

0.350 

0.479 

0.598 

0.897 

I. 

197 

1.496 

1.795 

900 

0.337 

0.404 

0.539 

0.673 

1.011 

1. 

346 

1.683 

2.020 

1,000 

0.374 

0.449 

0.598 

0.748 

1.122 

1. 

496 

1.870 

2.244 

2,000 

0.748 

0.898 

1.197 

1496 

2  244 

o 

992 

3.740 

4.488 

3,000 

1.122 

1.346 

1.795 

2.244 

3  .  366 

4. 

488 

5.610 

6.732 

4,000 

1.496 

1.795 

2.393 

2.992 

4.488 

5. 

849 

7.480 

8.976 

5,000 

1.870 

2.244 

2.992 

3.740 

5.610 

7. 

480 

9.350 

11.220 

6,000 

2.244 

2.692 

3.590 

4.488 

6.732 

8. 

976 

11.220 

13.464 

7,000 

2.618 

3.141 

•     4.189 

5.236 

7.854 

10. 

472 

13.090 

15.708 

8,000 

2.992 

3.590 

4.787 

5.984 

8.976 

11. 

968 

14.961 

17.953 

9,000 

3.366 

4.039 

5.385 

6.732 

10.098 

13. 

464 

16.831 

20.197 

10,000 

3.74 

4.488 

5.984 

7.480 

11.122 

14. 

961 

18.701 

22.441 

20,000 

7.48 

8.976 

11.968 

14.961 

22.443 

29. 

992 

37.402 

44.882 

30,000 

11.22 

13.46 

17.95 

22.44 

33.664 

44. 

88 

56.10 

67.32 

4D,000 

14.96 

17.95 

23 

.94 

29.92 

44.885 

59. 

84 

74.81 

89.77 

50,000 

18.70 

22.44 

29.92 

37.40 

56.103 

74. 

80 

93.50 

112.20 

60,000 

22.44 

26.92 

35.90 

44.88 

67.323 

89.76 

112.20 

134.64 

70,000 

26.18 

31.41 

41.89 

52.36 

78.543 

104. 

72 

130.90 

157.08 

80,000 

29.92 

35.90 

47.87 

59.84 

89.766 

119. 

68 

149.61 

179.53 

90,000 

33.66 

40.39 

53.85 

67.32 

100.986 

134. 

64 

168.31 

201.97 

100,000 

37.40 

44.88 

59.84 

74.80 

111.22 

149. 

61 

187.01 

224.41 

200,000 

74.81 

89.76 

119.68 

149.61 

224.43 

299. 

22 

374.02 

448.82 

300,000 

112.20 

134.64 

179.53 

224.41 

336.64 

448. 

83 

561.03 

673.24 

400,000 

149.61 

179.53 

239.37 

299.22 

448.85 

598. 

44 

748.05 

897.66 

500,000 

187.01 

224.41 

299.22 

374.02 

561.03 

748. 

05 

935.06 

1122.07 

600,000 

224.41 

269.29 

359.06 

448.83 

673.23 

897. 

66 

1122.07 

1346.49 

700,000 

261.81 

314.18 

418.90 

523.63 

785.43 

1047. 

27 

1309.08 

1570.88 

800,000 

299.22 

359.06 

478.75 

598.44 

897.66 

1196. 

88 

1496.10 

1795.32 

900,000 

336.62 

403.94 

538 

.59 

673.24 

1009.86 

1346. 

49 

1683.11 

2019.73 

1,000,000 

374.02 

448.83 

598.44 

748.05 

1122.06 

1498. 

10 

1870.12 

2244.15 

Table 

28-40 

.    Water  Conversion  Factors 

u. 

S.  gallons 

X     8.33 

=  pounds.       Cubic 

feet  of  water  (39 

.2°) 

X  62.427 

=  pounds. 

u. 

S.  gallons 

X     0.13368   =cubic  ft.      Cubic 

feet  of  water  (39 

.2°) 

X     7.48 

=  U.S.gal. 

u. 

S.  gallons 

X231.00 

=  cubic  in.      Cubic 

feet  of  water  (39 

.2°) 

X     0.028 

=  tons. 

u. 

S.  gallons 

X     3.78 

=  liters. 

Pounds  of  water 

X  27.72 

=  cubic  in. 

Cubic  inches  of  water  (39. 

2°)X     0.036130  = 

pounds 

Pounds  of  water 

X     0.01602 

=  cubic  ft. 

Cubic  inches  of  water  (39. 

2°)  X     0.004329  = 

U.S.  gal.      Pounds  of  water 

X     0.12 

=  U.S.  gal. 

Cubic  inches  of  water  (39 

.2°)  X     0.576384  = 

ounces. 

338 


Table  28-41.    Classification  of  Coals  * 


1  cu.  ft.  of  anthracite  coal  weighs  55  to  66  Ib. 
1  "  "  bituminous  "         "       50  to  55  Ib. 

1  "  "  semi-bituminous  coal  weighs  48  to  53  Ib. 


Name  of  coal 

Percentages  of  combustible 
Fixed  carbon                               Volatile  matter 

B.t.u.  per  pound 
of  combustible 

Anthracite            

97  0  to  92  5 

3.0to    7.5 
7.5  to  12.  5 
12.  5  to  25.0 
25.0  to  40.0 
35.0  to  50.0 
50  .  0  and  over 

14,600  to  14,800 
14,700  to  15,500 
15,500  to  16,000 
14,800  to  15,300 
13,500  to  14,800 
11,000  to  13,500 

Semi-anthracite  

92.5to87.5 

Semi-bituminous       

87  5  to  75  0 

Bituminous,  East  

75.0  to  60.0 

West     

65  0  to  50  0 

Lignite  

....         50  .  0  and  under 

*  HiirtliiiK  and  Willurd.  Mechanical  Equipment  of  Buildings.      Published  by  John  Wiley  &  Sons 

Table  28-42.     Names  and  Sizes  of  Bituminous  or  Soft  Coal  f 

For  "  Domestic  "  soft  coals  there  are  no  uniform  names  and  sizes,  but  they  are  marketed  in  the  various 
states  under  about  these  classes: 

Screenings  usually  smallest  sizes. 

Duff  goes  through  }^-in.  screen. 

No.  3  Nut  goes  through  l^£-in.  screen,  over  Ji-in.  screen. 

No.  2  Nut  goes  through  2-in.  screen,  over  IJ^-in.  screen. 

No.  1  Domestic  Nut  goes  through  3-in.  screen,  over  \Yi  or  2-in.  screen. 

No.  4  Washed  goes  through  H-in.  screen,  over  J4-in.  screen. 

No.  3  Washed  Chestnut  goes  through  IJ^-in.  screen,  over  Ji-in.  screen. 

No.  2  Washed  Stove  goes  through  2-in.  screen,  over  l}^-in.  screen. 

No.  1  Washed  Egg  goes  through  3-in.  screen,  over  2-in.  screen. 

No.  3  Roller  Screened  Nut  goes  through  l)^-in.  screen,  over  1-in.  screen. 

No.  2  Roller  Screened  Nut  goes  through  2-in.  screen,  over  IJ^-in.  screen. 

No.  1  Roller  Screened  Nut  goes  through  3J^-in.  screen,  over  2-in.  screen. 

Egg  goes  through  6-in.  screen,  over  3-in.  screen. 

Lump  or  Block  goes  through  6-in.  screen,  or  over. 

Run-of-Mine  in  fine  and  large  lumps. 

Pocahontas  Smokeless:  generally  sized  as:  Nut,  Egg,  Lump,  and  Mine-Run. 

•  Harding  and  Willurd 


Table  28-43.     Heat  Values  of  Bituminous  Coals  J 

From  selected  free-burning  and  caking  soft  fuels  taken  from  Bulletin  No.  332,  U.  S.  Geological  Survey,  and 

Bulletin  No.  23,  U.  S.  Bureau  of  Mines 


State 


Test 
No. 


Kind  of  fuel 


County 


B.t.u. 
per  Ib. 
dry  coal 


Alabama 375 

Alabama 484 

Arkansas 293 

Arkansas 308 

Arkansas 340 

Georgia 481 

Illinois 448 

Illinois 511 

Illinois 509 

Indiana 428 

Indiana 435 

Indiana 464 

Indian  Territory 437 

Indian  Territory 449 

Kansas 311 

Kentucky 434 


Soft— caking Bibb 13,671 

Soft — free  burning Jefferson 14,447 

Soft— caking Sebastian 13,705 

Semi-anthracite — caking Johnson 14,125 

IJgnite Quachita 9,549 

Soft— free  burning Chattooga 12,865 

Soft— free  burning Williamson 12,920 

Soft  briquettes St.  Clair 13,271 


Soft — caking Saline. . 

Soft — free  burning Greene. 

Soft — caking Pike .  .  . 

Soft  briquettes Parke. . 


13,621 
13,099 
13,545 
11,930 


Soft— free  burning 13,932 

Semi-anthracite 14,682 

Soft— free  burning Linn 12,343 

Soft — free  burning Union 14,026 


:  Harding  and  Willard 


339 


Table  28-44.    Heat  Values  of  Bituminous  Coals* — Continued 

From  selected  free-burning  and  caking  soft  fuels  taken  from  Bulletin  No.  332,  U.  S.  Geological  Survey  and 

Bulletin  No.  23,  U.  S.  Bureau  of  Mines 


State 


Test 
No. 


Kind  of  fuel 


County 


B.t.u. 
per  Ib. 
dry  coal 


Maryland 490 

Maryland 518 

Missouri 319 

Montana 477 

New  Mexico 392 

New  Mexico 387 

Ohio 483 

Pennsylvania 473 

Pennsylvania 499 

Pennsylvania 514 

Tennessee 409 

Tennessee 368 

Tennessee 363 

Texas 291 

Utah 404 

Virginia 482 

Virginia 507 

Washington 290 

Washington 359 

West  Virginia 305 

West  Virginia 439 

Wyoming 399 

Wyoming 400 


Soft — free  burning Allegany 14,515 

Soft  briquettes Allegany ,•  14,717 

Soft^caking Randolph 11,747 

Lignite — free  burning Carbon 11,628 

Soft— caking Colfax 13,059 

Soft— free  burning Colfax 12,721 

Soft— free  burning Belmont 13,381 

Soft — caking Indiana 14,240 


Soft — free  burning Cambria 

Soft  briquettes Westmoreland . 

Soft  briquettes Claiborne 

Soft — free,  burning Campbell 


14,119 
14,382 
14,092 
14,008 


Soft-^-caking Grundy 13,257 

Lignite — free  burning Wood 11,131 

Soft — free  burning Summit 12,586 

Anthracite — free  burning Montgomery 12,679 

Soft-making Tazewell 14,177 

Subbit — free  burning King 11,772 

Soft— free  burning Kittitas 12,996 

Soft — free  burning Marion 13,964 

Soft — caking Kanawha 13,995 

Soft— free  burning Carbon 12,222 

Subbit— free  burning Unita 12,488 


NOTE — These  values  were  obtained  at  the  St.  Louis  Testing  Plant  from  139  samples  of  coal.     The 
heating  values  of  the  various  coals  were  established  by  "actually  burning  one  gram  of  the  air-dried  coal  in 
oxygen  in  a  Mahler-bomb  calorimeter."     These  values  in  B.t.u.  give  the  theoretical  maximum  thermal 
value  of  soft  coals 
"Harding  &  Willard 

Table  28-45.     Names  and  Sizes  of  Anthracite  or  Hard  Coal  f 


Names  of  sizes 


Will  pass  through 


Will  not  pass  through 


Buckwheat  No.  1  
No.  2  

J^-in.  mesh 

}i-in.  mesh 

or  Rice  

M-in-  mesh 

J-6-in.  mesh 

Pea  

M-m.  mesh 

H-in.  mesh 

Chestnut,  or  Nut  

1^-in.  mesh 

M-in.  mesh 

Stove  or  Range  
Egg  —  in  the  East  

1  %-in.  mesh 
2J/£-in.  mesh 

1%-in.  mesh 
1%-in.  mesh 

Large  Egg  —  Chicago  
Small  Egg  —  Chicago  

4     -in.  mesh 
2%-in.  mesh 

2%-in.  mesh 
2    -in.  mesh 

Broken,  or  Grate  

4     -in.  mesh 

2J^-in.  mesh 

t  Harding  and  Willard 


Table  28-46.     Calorific  Value  of  Coal 

Where  a  complete  analysis  of  the  coal  is  not  obtainable  the  following  formula  may  be  used:  B.t.u.  per  Ib.  =  144  [100  —  (w+  a)] 
-  10.8  we,  where  w  and  a  are  the  percentages  of  water  and  ash,  and  c  is  a  constant  varying  with  the  amount  of  water.  When  w  < 
3%,  c  =  4;  when  w  is  between  3  and  4.5%,  c  =  6;  w  bet.  4.5  and  8.5%,  c  =  12;  w  bet.  8.5  and  12%,  c  =  10;  w  bet.  12  and  20%. 
c  =  8;  w  bet.  20  and  28%,  c  =  6;  w  >  28%,  c  =  4.  Also,  when  C  and  GI  are  the  percentages  of  fixed  and  volatile  carbon,  respec- 
tively, and  H  the  percentage  of  hydrogen,  B.t.u.  per  Ib.  =  (14,600  C  +  20,390  Ci  +  62,000  H)  +  100 

340 


Table  28-47.     Composition  and  Heat  Values  of  Anthracite  Coal  * 


Locality 

Fixed 

car- 
bon 

Vola- 
tile 

Mois- 

turc 

Ash 

Sul- 
phur 

B.l.u 
per  Ib. 
of  dry 
coal 

Anthracite 

Pennsylvania  

78.60 

14.80 

0.40 

Buckwheat  

81.32 

3.84 

3.88 

10.96 

0.67 

12,200 

Wilkes-Barre  ,  

76.94 

6.42 

1.34 

15.30 

11,801 

Scran  ton  '.  

79.23 

3.73 

3.33 

13.70 

12,149 

Scranton  

84.46 

5.37 

0.97 

9.20 

•  >  *  • 

12,294 

Cross  Creek  

89.19 

1.96 

3.62 

5.23 



13,723 

Lehigh  Valley  

75.20 

7.36 

1.44 

16.00 

12,423 

Lykens  Valley  

76.94 

6.21 

15,300 

Lykens  Valley  
\V  barton  

81.00 
86.40 

5.00 
3.08 

3.71 

6.22 

0.58 

15,300 
15,000 

Buck  Ml  

82.66 

3.95 

3.04 

9.88 

0.46 

15,070 

Beaver  Meadow  

88.94 

2.38 

1.50 

7.11 

0.01 

Lackawanna  

87.74 

3.91 

9    J9 

6.35 

0.12 

Rhode  Island  

85.00 

7  00 

0  90 

Arkansas  

74.49 

14.73 

1.52 

9.26 

13,217 

Semi-Anthracite 

Pennsylvania,  Loyalsock  

83.34 

8.10 

1.30 

6.23 

1.03 

15,400 

Bernice  

82.52 

3.56 

0.96 

3.27 

0.24 

15,050 

Bernice  

89.39 

8.56 

0.97 

9.34 

1.04 

15,475 

Wilkes-Barre  

88.90 

7.68 

3.49 

14,199 

Lycoming  Creek  

71.53 

13  84 

0  67 

13  96 

0  03 

Virginia,  Natural  Coke  

75.08 

12.44 

1.12 

11.38 

0.47 

Arkansas  

74.06 

14.93 

1.35 

9.66 

Indian  Territory  

73.21 

13.65 

5.11 

8.03 

1.18 

13,662 

Maryland,  Easby  

83.60 

16.40 

11,207 

•HurdiiiK  &  Willard 


Table  28-48.     Weight  of  Materials 
Dry  woods 


Material 
Ash  

Weight   in 
Ib.  of  one 
cu.  ft. 

43-53 

Weight    in 
Material                       Ib.  of  one 
cu.  ft. 

Fir,  Spruce        .    .               30-44 

Material 

Weight  in 
Ib.  of  one 
cu.  ft. 

54 

Beech  

43-53 

48-58 

Birch  

40-46 

Hornbeam     ....          .           47 

.     30-44 

Boxwood  

57-83 

Larch                                  31-37 

27-34 

Cork  

15 

Lignum-vitar        .  .                   83 

..     29-41 

Ebony    . 

70-83 

Teak 

41-55 

Elm          

34-45 

Stones,  earth,  etc. 


Material 
Asphaltum          

Weight  in 
Ib.  of  one 
cu.  ft. 

.  .      64-112 

Material 

Weight   in 
Ib.  of  one 
cu.  ft. 

187 

Weight  in 
Material                       Ib.  of  one 
cu.  ft. 

Mud  —  dry  Hn(|  close           80-110 

Brick  —  common  

.  .   100-125 

169 

"       wet  and  fluid         104-120 

"         fire  

.  .   137-150 

161-175 

Sand  —  dry               .        .     88-110 

Cement  —  Portland  .  .  . 

.  .     80-90 

Gravel   

90-125 

wet        118-129 

Clay  

120 

Grindstone 

134 

Sandstone                .        .   130-170 

.  .   120-140 

5° 

Earth   ...           

77-120 

no  179 

156 

88  118 

341 


Table  28-49.     Weight  of  Materials 
Metals  and  Alloys 


-Continued 


Material 


Specific 
gravity 


Weight  in  Ib. 

of  one 
cu.  ft.  cu.  in. 


Cu.  in. 

in  one 

Ib. 


Aluminum — cast 2. 569 

wrought 2.681 

bronze 7. 787 

Antimony 6.712 

Arsenic 5. 748 

Bismuth 9 . 827 

I  from  7.868 

Brass — cast |  to  8. 430 

(average  8.109 

Muntz  metal 8.221 

naval  (rolled) 8. 510 

"        sheet 8 . 462 

wire 8.558 

I  from  8.478 

Bronze  (gun-metal). .  . < to  8 . 863 

(average  8.735 

Copper— cast 8. 622 

hammered 8 . 927 

sheet 8.815 

wire 8.895 

Gold  (pure) 19. 316 

"     standard  22  carat  fine 17. 502 

(Gold  11— Copper  1) 

[from  6 . 904 

Iron — cast |  to  7 . 386 

(average  7.209 

I  from  7.547 

Iron— wrought <  to  7 . 803 

(average  7.707 

Lead— cast 11 . 368 

"        sheet 11 . 432 

Manganese 8. 012 

Nickel— cast 8. 285 

rolled 8.687 

Platinum 21 . 516 

Silver 10.517 

[from  7.820 

Steel |to  7.916 

(average  7.868 

Tin 7.418 

White  Metal  (Babbitt's) 7 . 322 

Zinc— cast 6. 872 

sheet..  7.209 


160 
167 
485 
418 
358 

612 
490 
525 
505 
512 
530 

527 
533 
528 
552 
544 
537 
556 

549 

554 

1203 

1090 

430 
499 

464 
470 
486 
480 

708 
712 
499 
516 
541 

1340 
655 
487 
493 
490 

462 
456 
428 
449 


.093 
.097 
.281 
.242 
.207 

.354 
.284 
.304 
.292 
.296 
.307 

.305 
.308 
.306 
.319 
.315 
.311 
.322 

.318 
.321 
.696 
.631 

.249 
.266 
.260 
.272 
.281 
.278 

.410 
.412 
.289 
.299 
.313 

.775 
.379 
.282 
.285 
.284 

.267 
.264 
.248 
.260 


10.80 

10.35 

3.56 

4.13 

4.83 

2.82 
3.53 
3.29 
3.42 
3.37 
3.26 

3.28 
3.24 
3.27 
3.13 
3.18 
3.22 


3.11 

3.15 
3.12 
1.44 
1.59 


4.02 
3.76 
3.85 
3.56 
3.68 
3.60 


2.44 
2.43 
3.46 
3.35 


3.19 


1.29 
2.64 
3.55 
3.51 
3.53 

3.74 
3.79 
4.04 
3.85 


Table  28-50.    Specific  Heat  and  Densities  of  Building  Materials  * 


Building  materials 


Specific 
heat 


Building  materials 


Specific 
heat 


Brickwork 0.1950 

Concrete 0.2700 

Masonry 2159 

Plaster 2000 

Pinewood .  .  .  4670 


Oakwood 0.5700 

Birch 4800 

Glass 1977 

Steel 1165 


Densities  in  16  per  cu.  ft. 


Stonework. 

Wood 

Slate 

Plaster. .  .  . 


160 
40 

170 
90 


'Harding  and  Willard 


342 


Table  28-51.     Specific  Heats  of  Various  Substances  f 


Solids 


C.OPIHT 

Temperature,* 
degrees 
fahrenheit 

59-460 

Specific 
heat 

0.0951 
.0316 
.1152 
.1200 
.1175 
.1165 
.0935 
.0883 

Glass  (normal  ther.  16'"). 

Temperature,* 
degrees 
fahrenheit 

66-212 
59 

Specific 
beat 

0.1988 
.0299 
.0323 
.0559 
.0518 
.5040 
.2025 

Gold 

32-212 

Wrought  iron       .... 

59-212 

32-212 

Cast  iron  

68-212 

32-212 

Steel  (hard)       

68-208 

Tin  

.  .     105-64 

Steel  (soft)  

68-208 

Ice   

Zinc    

32-212 

Sulphur  (newly  fused) 

Brass   (yellow)  

32 

Liquids 


Water  

1 

'emperature,* 
degrees 
fahrenheit 

59 

132 
U76 
32 
/50 
1122 
59-102 

to  360 

Specific 
heat 

1.0000 
0.5475 
.7694 
.3346 
.4066 
4502 

Sulphur  (melted) 
Tin  (melted)  

Te 
1 

mperature,* 
degrees 
ahrenheit 

246-297 

Specific 
heat 

0.2350 
.637 
.980 
.903 
.411 
.498 
.3363 
.309 

Alcohol 

Mercury  

Sea-water  (sp.  gr. 
Sea-water  (sp.  gr. 
Oil  of  turpentine 
Petroleum  

1.0043)  
1.0463)  .... 

64 
64 
32 
64-210 
68-133 

Benzol 

Glycerine  

Lead  (melted) 

.0410 

Olive  oil  

Gases 

Air  

Tempera- 
ture,* 
degrees 
fahrenheit 

32-392 
55-405 
32-392 
54-388 

Specific 
heat  at 
constant 
pressure 

0.2375 
.2175 
.2438 
3.4090 

Specific 
heat  at 
constant 
volume 

0.1693 
.1553 
.1729 
2.4141 

Tempera- 
ture,* 
degrees 
fahrenheit 

Carbon  monoxide.  .  .  .     41-208 

Specific 
heat  at 
constant 
pressure 

0.2425 
.2169 
.5929 

.2277 
.2400 

Specific 
heat  at 
constant 
Tolume 

0.1728 
.1535 
.4505 

Ox\fgen 

Nitrogen  

64-406 

Hydrogen 

Blast-fur,  gas  (a] 
Flue  gas  (approx. 

*  When  one  temperature  alone  is  given  the  "true"  specific  heat  is  given;  otherwise  the  value  is  the  "mean11  specific  heat  fur  the 
range  of  temj>eratiire  riven 

i  II;, r. li.it;  and  Willard 

Table  28-52.     Tensile  Strength  of  Materials 
Average  value  in  pounds  per  square  inch 


Antimony 1053 

Aluminum — castings 15000 

sheet 24000 

bars 28000 

Brass — yellow 26880 

Bronze — cast 34000 

delta  metal— cast  -14800 
"   rolled  67200 

gun  metal 32000 

phosphor 40000 

manganese 62720 

Tobin 78500 

Copper— cast 22400 

sheet 30240 

wire 40000 

Cast  Steel  .80000 


Gold 

Iron — cast . 


wrought 

Lead — cast 

rolled  sheet 

Platinum  wire 

Puddled  semi-steel 

35000  to 

Silver — cast 

Steel — cast 60000  to 

forgings.    60000  to 

Tin — cast 

Zinc — cast 

sheet 

343 


20384 

25000 

18000 

45000 

1800 

3320 

53000 

42000 

40000 

80000 

95000 

3360 

3360 

15680 


Woods 

Ash 11000  to  17000 

Beech 11500  to  18000 

Cedar 10300  to  11400 

Chestnut 10500 

Elm 13000  to  13489 

Hemlock 8700 

Hickory 12800  to  18000 

Locust 20500  to  24800 

Maple 10500  to  10584 

Oak— white 10253  to  19500 

Pine— white 10000  to  12000 

yellow 12600  to  19200 

Spruce 10000  to  19500 

Walnut,  black  . .  9286  to  16000 


Table  28-53.     Lineal  Expansion  of  Solids  at  Ordinary  Temperatures 

(Tabular  values  represent  increase  per  foot  per  100-deg.  increase 
in  temperature,  fahr.  or  cent.) 


Substance 

Temperature 
conditions* 
deg.  fahr. 

Coefficient  per  100 
deg.  fahr. 

Coefficient  per  100 
deg.  cent. 

Brass 
Brass 
Coppt 
Glass 

Glass 
Gold 

(cast)        .  .  . 

32 
321 
321 

321 

32 
32 

321 

0 
32 
32 
32 

32 
0 
0 

to  212 
jo  212 
jo  212 
jo  212 

to  212 
to  212 
to  212 
104 

to  212 
to  212 
to  212 
to  212 

104 

to  212 
104 
to  212 

to  212 
104 
104 

.  001042 
.  001072 
.  000926 
.000451 

.  000484 
.  000816 
.  000482 
.  000589 

.  000634 
.000800 
.  001505 
.  0099841 

.  000499 
.000139 
.001067 
.00056 

.  00063 
.000734 
.000608 

.  001875 
.  001930 
.  001666 
.  000812 

.  000872 
.  001470 
.  000868 
.001061 

.001141 
.  001440 
.002709 
.017971t 

.  000899 
.  000251 
.  001921 
.00101 

.00117 
.  001322 
.  001095 

r      

(English  flint 
(French  flint 

) 

>         

Grani 
Iron  ( 

Iron  ( 
Iron  ( 
Lead 

be  (average) 

cast) 

soft  forged) 

Merci 

Platin 
Limes 
Silver 
Steel 

Steel 
Steel 
Steel 

Bessemer  rol 

Bessemer  ro 
cast,  French 
cast  anneale 

led,  hard)          .  .  . 

led   soft) 

)           

1   English) 

*  Where  range  of  temperature  is  given,  coefficient  is  mean  over  range 
t  Coefficient  of  cubical  expansion 

Table  28-54.     Decimal  Equivalents  of  Fractions  of  an  Inch 

Fractions 

i 
Decimals 

Fractions 

Decimals 

Fractions 

Decimals 

? 

i 

32               •   • 

"       A 

.015625 
.03125 
.046875 
.0625 

.078125 
.09375 
.109375 

y*    -125 

H       -. 

*   « 

21 
64               •  • 

H       '•'• 

•  •       M 

i 

3 

7 
16 

.359375 
8        .375 
.390625 
.40625 

.421875 
.4375 
.453125 
.46875 

23 

an 
tt          .- 

if          •• 

H 

tt      •• 

H 

.703125 
.71875 
.734375 

.75 

.765625 
.78125 
.796875 
.8125 

344 


Table  28-55.    Decimals  of  a  Foot  for  Inches  and  Fractions  of  an  Inch 


Inch 

10" 

11" 

0 

0 

.0833 

.1667 

.2500 

.3333 

.4167 

.5000 

.5833 

.6667 

.7500 

.8333 

.9167 

A 

.0026 

.0859 

.1693 

.2526 

.3359 

.4193 

.5026 

.5859 

.6693 

.7526 

.8359 

.9193 

A 

.0052 

.0885 

.1719 

.2552 

.3385 

.4219 

.5052 

.5885 

.6719 

.7552 

.8385 

.9219 

A 

.0078 

.0911 

.1745 

.2578 

.3411 

.4245 

.5078 

.5911 

.6745 

.7578 

.8411 

.9245 

H 

.0101 

.0937 

.1771 

.2604 

.  3437 

.4271 

.5104 

.5937 

.6771 

.  7604 

.8437 

.9271 

A 

.0130 

.0961 

.1797 

.2630 

.3464 

.4297 

.5130 

.5964 

.6797 

.7630 

.8464 

.9297 

A 

.0156 

.0990 

.1823 

.2656 

.3490 

.4323 

.5156 

.5990 

.6823 

.7656 

.8490 

.9323 

£ 

.0182 

.1016 

.1849 

.2682 

.3516 

.4349 

.5182 

.6016 

.6849 

.7682 

.8516 

.9349 

K 

.0208 

.1042 

.1875 

.2708 

.3542 

.4375 

.5208 

.6042 

.6875 

.7708 

.  8542 

.9375 

A 

.  0234 

.1068 

.1901 

.2734 

.3568 

.4401 

.5234 

.6068 

.6901 

.7734 

.8568 

.9401 

A 

.0260 

.  1094 

.1927 

.2760 

.3594 

.4427 

.5260 

.6094 

.6927 

.7760 

.8591 

.9427 

H 

.0286 

.1120 

.1953 

.2786 

.3620 

.4453 

.5286 

.6120 

.6953 

.7786 

.8620 

.9453 

Ji 

.0312 

.1146 

.1979 

.2812 

.3646 

.4479 

.5312 

.6146 

.6979 

.7812 

.  8646 

.9479 

H 

.0339 

.1172 

.2005 

.2839 

.3672 

.4505 

.5339 

.6172 

.  7005 

.7839 

.8672 

.9505 

.  0365 

.1198 

.2031 

.2865 

.  3698 

.4531 

.5365 

.6198 

.7031 

.7865 

.8698 

.9531 

.0391 

.1221 

.2057 

.2891 

.3724 

.4557 

.5391 

.6224 

.7057 

.7891 

.8724 

.9557 

H 

.0117 

.1250 

.  2083 

.2917 

.3750 

.4583 

.5417 

.6250 

.7083 

.7917 

.  8750 

.9583 

H 

.0443 

.1276 

.2109 

.2943 

.3776 

.4609 

.5443 

.6276 

.7109 

.  7943 

.8776 

.9609 

A 

0169 

.1302 

.2135 

.2969 

.3802 

.4635 

.5469 

.6302 

.7135 

.7969 

.8802 

.9635 

if 

.OJ95 

.1328 

.2161 

.2995 

.3828 

.4661 

.5495 

.6328 

.7161 

.  7995 

.8828 

.9661 

^8 

.  0521 

.  1354 

.2188 

.3021 

.  3854 

.4688 

.  5521 

.6354 

.7188 

.8021 

.  8854 

.9688 

H 

.0547 

.1380 

.2214 

.  3047 

.  3880 

.4714 

.5547 

.6380 

.7214 

.8047 

.8880 

.9714 

H 

.0573 

.1406 

.  2240 

.3073 

.3906 

.4740 

.  5573 

.6406 

.7240 

.8073 

.8906 

.9740 

8 

.  0599 

.1432 

.2266 

.3099 

.3932 

.  4766 

.5599 

.6432 

.7266 

.8099 

.8932 

.9766 

« 

.  0625 

.  1458 

2292 

.3125 

.3958 

.4792 

.5625 

.6458 

.7292 

.8125 

.  8958 

.9792 

H 

.0651 

1  IKI 

.2318 

.3151 

.3984 

.4818 

.5651 

.6484 

.7318 

.8151 

.  8984 

.9818 

H 

.0677 

.1510 

.2344 

.3177 

.4010 

.4844 

.5677 

.6510 

.  7344 

.8177 

.9010 

.9844 

H 

.0703 

1536 

.2370 

.3203 

.4036 

.4870 

.5703 

.6536 

.7370 

.8203 

.9036 

.9870 

H 

.0729 

.1562 

.2396 

.3229 

.4062 

.4896 

.5729 

.6562 

.7396 

.8229 

.9062 

.9896 

.0755 

.1589 

.2422 

.3255 

.4089 

.4922 

.5755 

.6589 

.7422 

.8255 

.9089 

.9922 

II 

.0781 

.1615 

.2448 

.3281 

.4115 

.4948 

.5781 

.6615 

.7448 

.8281 

.9115 

.9948 

H 

.0807 

.1641 

.2474 

.3307 

.4141 

.4974 

.5807 

.6641 

.7474 

.8307 

.  9141 

.9974 

i 

1.0000 

Table  28-56.    Decimals  of  a  Foot  Equivalent  to  Inches  and  Fractions 

of  an  Inch 


Inches 

0" 

X" 

M" 

H" 

H" 

H" 

K" 

X" 

0 

0 

.  01042 

.02083 

.03125 

.04166 

.05208 

.06250 

.07292 

1 

.0833 

.0937 

.1042 

.1146 

.1250 

.1354 

.1459 

.1563 

2 

.1667 

.1771 

.  1875 

.1979 

.2083 

.2188 

.2292 

.2396 

3 

.2500 

.2604 

.2708 

.2813 

.2917 

.3021 

.3125 

.3229 

4 

.3333 

.3437 

.3542 

.3646 

.3750 

3854 

.3958 

.4063 

5 

.4167 

.4271 

.4375 

.4479 

.4583 

.4688 

.4792 

.4896 

6 

.5000 

.5104 

.5208 

.5313 

.5417 

.5521 

.5625 

.5729 

7 

.5833 

.5937 

.  6042 

.6146 

.6250 

.6354 

.6459 

.6563 

8 

.6667 

.6771 

.6875 

.6979 

.7083 

.7188 

.7292 

.7396 

9 

.7500 

.  7604 

.7708 

.7813 

.7917 

.8021 

.  8125 

.8229 

10 

.  8333 

.  8437 

.8542 

.8646 

.8750 

.8854 

.  8958 

.9063 

11 

.9167 

.9271 

.9375 

.9t79 

.9583 

.9688 

.9792 

.9896 

345 


Table  28-57.     Circumferences  and  Areas  of  Circles 
Advancing  by  Eighths 


DUm. 

Circum. 

Area 

Diam 

Circum. 

Area 

Diam 

Circum. 

Area 

Diam 

Circum. 

Area 

A 

.0490 

.0001 

2-H 

8.4430 

5.6727 

7. 

21.991 

38.485 

14.  J4 

44.768 

159.48 

A 

.0981 

.0007 

H 

8.6394 

5.9396 

1A 

22.384 

39.871 

H 

45.160 

162.30 

A 

.1472 

.0017 

H 

8.8357 

6.2126 

H 

22.776 

41.282 

M 

45.553 

165.13 

A 

.1963 

.0030 

H 

9.0321 

6.4918 

H 

23.169 

42.718 

N 

45.946 

167.99 

A 

.2945 

.0069 

H 

9.2284 

6.7771 

M 

23.562 

44.179 

H 

46.338 

170.87 

X 

.3927 

.0122 

H 

23.955 

45.664 

H 

46.731 

173.78 

A 

.4908 

.0191 

3. 

9.4248 

7.0686 

3A 

24.347 

47.173 

A 

.  5890 

.0276 

A 

9.6211 

7.3662 

% 

24.740 

48.707 

15. 

47.124 

176.71 

A 

.  68722 

.0375 

1A 

9.8175 

7.6699 

H 

47.517 

179.67 

A 

10.014 

7.9798 

8. 

25.133 

50.265 

H 

47.909 

182.65 

¥ 

.  78540 

.  04909 

X 

10.210 

8.2958 

H 

25.525 

51.849 

N 

48.302 

185.66 

A 

.88357 

.0621 

A 

10.407 

8.6179 

1A 

25.918 

53.456 

1A 

48.695 

188.69 

.98175 

.07670 

H 

10.603 

8.9462 

H 

26.311 

55.088 

N 

49.087 

191.75 

1  .  0799 

.0928 

A 

10.799 

9.2806 

1A 

26.704 

56.745 

H 

49.480 

194.83 

/» 

1.1781 

.11045 

% 

10.996 

9.6211 

H 

27.096 

58.426 

y» 

49.873 

197.93 

if 

1.2763 

.  12962 

9 
1~6 

11.192 

9.9678 

y\ 

27.489 

60.132 

A 

1.3744 

.  15033 

S 

11.388 

10.321 

% 

27.882 

61.862 

16. 

50.265 

201.06 

H 

1.4726 

.  17257 

« 

11.585 

10.680 

y« 

50.658 

204.22 

H 

11.781 

11.045 

9. 

28.274 

63.617 

% 

51  .  051 

207.39 

y2 

1  .  5708 

.  19635 

H 

11.977 

11.416 

y& 

28.667 

65.397 

3A 

51.414 

210.60 

H 

1  .  6690 

.22166 

H 

12.174 

11.793 

% 

29.060 

67.201 

Vi 

51.836 

213.82 

A 

1.7671 

.24850 

H 

12.370 

12.177 

3A 

29.452 

69.029 

N 

52.229 

217.08 

H 

1.8653 

.27688 

1A 

29.845 

70.882 

% 

52.622 

220.35 

5x( 

1  .  9635 

.  30680 

4. 

12.566 

12.566 

H 

30.238 

72.760 

8 

53.014 

223.65 

fi 

2.0617 

.33824 

A 

12.763 

12.962 

R 

30.631 

74.662 

H 

2.1598 

.  37122 

H 

12.959 

13.364 

H 

31  .  023 

76.589 

17. 

53.407 

226.98 

If 

2.2580 

.  40574 

A 

13.155 

13.772 

H 

53.800 

230.33 

k 

13.352 

14.186 

10. 

31.416 

78.540 

1A 

54.192 

233.71 

« 

2.3562 

.44179 

A 

13.548 

14.607 

y* 

31  .  809 

80.516 

y* 

54.585 

237.10 

H 

2.4544 

.  47937 

« 

13.744 

15.033 

% 

32.201 

82.516 

1A 

54.978 

240.53 

if 

2.5525 

.  51849 

A 

13.941 

15.466 

3A 

32.594 

84.541 

N 

55.371 

243.98 

fi 

2.6507 

.  55914 

« 

14.137 

15.904 

1A 

32.987 

86.590 

% 

55.763 

247.45 

% 

2.7489 

.60132 

9 
T6 

14.334 

16.349 

H 

33.379 

88.664 

y* 

56.156 

250.95 

If 

2.8471 

.  64504 

N 

14.530 

16.800 

N 

33.772 

90.763 

if 

2.9452 

.  69029 

H 

14.726 

17.257 

H 

34.165 

92.886 

18. 

56.549 

254.47 

fi 

3.0434 

.  73708 

M 

14.923 

17.721 

y% 

56.941 

258.02 

H 

15.119 

8.190 

11. 

34.558 

95.033 

% 

57.334 

261.59 

1. 

3.1416 

.  7854 

H 

15.315 

18.665 

H 

34.950 

97.205 

N 

57.727 

265.18 

A 

3.3379 

.8866 

H 

15.512 

19.147 

« 

35.343 

99.402 

1A 

58.119 

268.80 

& 

3.5343 

.9940 

H 

35.736 

01.62 

% 

58.512 

272.45 

A 

3.7306 

1.1075 

5. 

15.708 

9.635 

H 

36.128 

03.87 

H 

58.905 

276.12 

% 

3.9270 

1  .  2272 

A 

15.904 

20.129 

M 

36.521 

06.14 

V* 

59.298 

279.81 

A 

4.1233 

1.3530 

H 

16.101 

20.629 

M 

36.914 

08.43 

N 

4.3197 

1  .  4849 

A 

6.297 

21.135 

% 

37.306 

10.75 

9. 

59.690 

283.53 

A 

4.5160 

1  .  6230 

H 

6.493 

21.648 

H 

60.083 

287.27 

H 

4.7124 

1.7671 

A 

6.690 

92.166 

2 

37.699 

13.10 

« 

60.476 

291  .  04 

A 

4.9087 

1.9175 

K 

6.886 

2.691 

'H 

38.092 

15.47 

H 

60.868 

294.83 

» 

5.1051 

2.0739 

A 

7.082 

3.221 

M 

38.485 

17.86 

y?. 

61.261 

298.65 

H 

5.3014 

2.2365 

« 

7.279 

3.758 

N 

38.877 

20.28 

5A 

61.654 

302.49 

K 

5.4978 

2.4053 

9 
IT 

7.475 

4.301 

J< 

39.270 

22.72 

Yi 

62.046 

306.  35 

H 

5.6941 

2.5802 

M 

7.671 

4.850 

M 

39.663 

25.19 

% 

62.439 

310.24 

•  x 

5.8905 

2.7612 

» 

7.868 

5.406 

H 

40.055 

27.68 

n 

6.0868 

2.9483 

B 

8.064 

5.967 

H 

40.448 

30.19 

0. 

62.832 

314.16 

H 

8.261 

6.535 

y» 

63.225 

318.10 

2. 

6.2832 

3.1416 

J^ 

8.457 

7.109 

3. 

40.841 

32.73 

H 

63.617 

322.06 

A 

6.4795 

3.3410 

ii 

8.653 

7.688 

H 

41  .  233 

35.30 

H 

64.010 

326.05 

1A 

6.6759 

3.5466 

k 

41  .  626 

37.89 

H 

64.403 

330.06 

A 

6.8722 

3.7583 

6. 

8.850 

8.274 

H 

42.019 

40.50 

N 

64.795 

334.10 

M 

7.0686 

3.9761 

H 

9.242 

9.465 

H 

42.412 

43.14 

k 

65.188 

338.16 

A 

7.2649 

4.2000 

M 

9.635 

0.680 

M 

42.804 

45.80 

H 

65.581 

342.25 

H 

7.4613 

4.4301 

H 

0.028 

1.919 

« 

43.197 

48.49 

A 

7.6576 

4.6664 

1A 

0.420 

3.183 

y? 

43.590 

51.20 

1. 

65.973 

346.36 

fc 

7.8540 

4.9087 

H 

0.813 

4.472 

H 

66.366 

350.50 

A 

8.050" 

5.1572 

P 

1.206 

5.785 

4. 

43.982 

53.94 

« 

66.759 

354.66 

« 

8.2467 

5.4119 

Ji 

1.598 

7.122 

H 

44.375 

56.70 

?i 

67.152 

358.84 

346 


Table  28-57.     Circumferences  and  Areas  of  Circles 
Advancing  by  Eighths — Continued 


Diam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

21.  H 

<>7  :>u 

363.05 

28.^ 

90.321 

649.18 

36. 

113.097 

1017.9 

43.^ 

135.874 

1469.1 

% 

67.937 

367.28 

H 

90.713 

654.84 

X 

113.490 

1025.0 

H 

136.267 

1477.6 

'A 

68.330 

:i:i  :,l 

H 

113.883 

1032.1 

1A 

136.659 

1486.2 

% 

68.722 

:?7.->  »:! 

29. 

91.106 

660.52 

8 

114.275 

1039.2 

R 

137.052 

1494.7 

Ys 

91  .  499 

666.23 

1A 

114.668 

1046.3 

H 

137.445 

1503.3 

22. 

69.115 

380.13 

91.892 

671.96 

% 

115.061 

1053.5 

H 

137.837 

1511.9 

H 

69.508 

384.46 

a 

92.284 

677.71 

« 

115.454 

1060.7 

K 

69.900 

388.82 

j/^ 

92.677 

683.49 

H 

115.846 

1068.0 

44. 

138.230 

1520.5 

H 

70.293 

393.20 

% 

93.070 

689.30 

y» 

138.623 

1529.2 

0 

70.686 

397.61 

% 

93.462 

695.13 

37. 

116.239 

1075.2 

M 

139.015 

1537.9 

71.079 

402.04 

% 

93.855 

700.98 

% 

116.632 

1082.5 

% 

139.408 

1546.6 

% 

71.471 

406.49 

X 

117.024 

1089.8 

1A 

139.801 

1555.3 

% 

71.864 

410.97 

30. 

94.248 

706.86 

*A 

117.417 

1097.1 

K 

140.194 

1564.0 

H 

94.640 

712.76 

1A 

117.810 

1104.5 

M 

140.586 

1572.8 

23. 

72.257 

415.48 

H 

95.033 

718.69 

H 

118.202 

1111.8 

% 

140.979 

1581.6 

H 

72.649 

420.00 

H 

95.426 

724.64 

K 

118.596 

1119.2 

Ji 

73.042 

424.56 

H 

95.819 

730.62 

H 

118.988 

1126.7 

45. 

141.372 

1590.4 

% 

73.435 

129.13 

H 

96.211 

736.62 

H 

141.764 

1599.3 

H 

73.827 

433.74 

x 

96.604 

742.64 

38. 

119.381 

1134.1 

y\ 

142.157 

1608.2 

H 

74.220 

438.36 

H 

96.997 

748  69 

y* 

119.773 

1141.2 

% 

142.550 

1617.0 

X 

74.613 

443.01 

u 

120.166 

1149.2 

1A 

142.942 

1626.0 

8 

75.006 

447.69 

31. 

97.389 

754.77 

K 

120.559 

1156.6 

% 

143.335 

1634.9 

H 

97.782 

760.87 

H 

120.951 

1164.2 

H 

143.728 

1643.9 

24. 

75.398 

452.39 

H 

98.175 

766.99 

y% 

121.344 

1171.7 

J4 

144.  121 

1652.9 

H 

75.791 

457.11 

« 

98.567 

773.14 

Y*. 

121.737 

1179.3 

y 

76.184 

461.86 

1A 

98.960 

779.31 

H 

122.129 

1186.9 

46. 

144.513 

1661.9 

H 

76.576 

466.64 

H 

99.353 

785.51 

H 

144.906 

1670.9 

H 

76.969 

471.44 

3 

99.746 

791  .  73 

39. 

122.522 

1194.6 

« 

145.299 

1680.0 

H 

77.362 

476.26 

8 

100.138 

797.98 

Ys 

122.915 

1202.3 

N 

145.691 

1689.1 

II 

77.754 

481.11 

y* 

123.308 

1210.0 

M 

146.084 

1698.2 

J5 

78.147 

485.98 

32. 

100.531 

804.25 

% 

123.700 

1217.7 

N 

146.477 

1707.4 

H 

100.924 

810.54 

1A 

124.093 

1225.4 

w 

146.869 

1716.5 

25. 

78.540 

490  87 

K 

101.316 

816  86 

H 

124.486 

1233.2 

K 

147.262 

1725.7 

H 

78.933 

495.79 

H 

101.709 

823.21 

% 

124.878 

1241.0 

y 

79.325 

500.74 

H 

102.102 

829  58 

% 

125.271 

1248.8 

47. 

147.655 

1734.9 

H 

79.718 

505.71 

H 

102.494 

835.97 

M 

148.048 

1744.2 

H 

80.111 

510.71 

3/i 

102.887 

842  39 

to. 

125.664 

1256.6 

« 

148.440 

1753.5 

K 

80.503 

515.72 

% 

103.280 

848  83 

H 

126.056 

1264.5 

R 

148.833 

1762.7 

H 

80.896 

520.77 

1A 

126.449 

1272.4 

>i 

149.226 

1772.1 

H 

81  .  289 

525.84 

33. 

103.673 

855.30 

% 

126  842 

1280.3 

5^ 

149.618 

1781.4 

y* 

104.065 

861  .  79 

1A 

127.235 

1288.2 

3xi 

150.011 

1790.8 

26. 

81  .  681 

530.93 

H 

104.458 

868.31 

% 

127.627 

1296.2 

J^ 

150.404 

1800.1 

H 

82.074 

536.05 

H 

104.851 

874.85 

*A 

128.020 

1301.2 

H 

82.467 

541.19 

H 

105.243 

881.41 

H 

128.413 

1312.2 

48. 

150.796 

1809.6 

H 

82.860 

546.35 

H 

105.636 

888.00 

J^ 

151.189 

1819.0 

H 

83.252 

551  .  55 

y 

106.029 

894.62 

u. 

128.805 

1320.3 

« 

151.582 

1828.5 

H 

83.645 

556.76 

H 

106.421 

901  .  26 

H 

129.198 

1328.3 

N 

151.975 

1837.9 

K 

84.038 

562.00 

H 

129.591 

1336.4 

Ji 

152.367 

1847.5 

j? 

84.430 

567.27 

34. 

106.814 

907.92 

H 

129.983 

1344.5 

M 

152.760 

1857.0 

H 

107.207 

914.61 

H 

130.376 

1352.7 

3X 

153.153 

1866.5 

27. 

84.823 

572.56 

H 

107.600 

921.32 

N 

130.769 

1360.8 

8 

153.545 

1876.1 

*i 

85.216 

577.87 

3/i 

107.992 

928.06 

H 

131.161 

1369.0 

H 

85.608 

583.21 

H 

108.385 

934.82 

H 

131.554 

1377.2 

w. 

153.938 

1885.7 

H 

86.001 

588.57 

H 

108.778 

941.61 

y% 

154.331 

1895.4 

H 

86.394 

593.96 

H 

109.170 

948.42 

42. 

131.917 

1385.4 

y* 

154.723 

1905.0 

H 

86.786 

599.37 

8 

109.563 

955.25 

H 

132.340 

1393.7 

Ys 

155.116 

1914.7 

54 

87.179 

601.81 

H 

132.732 

1402.0 

N 

155.509 

1924.4 

7/S 

87.572 

610.27 

35. 

109.956 

962.11 

M 

133.125 

1410.3 

H 

155.902 

1934.2 

H 

110.348 

969.00 

y* 

133.518 

1418.6 

R 

156.294 

1943.9 

28. 

87.965 

615.75 

H 

110.741 

975.91 

M 

133.910 

1427.0 

Ji 

156.687 

1953.7 

H 

88.357 

621.26 

K 

111.134 

982.84 

*A 

134.303 

1435.4 

J4 

88.750 

626.80 

H 

111.527 

989.80 

H 

134.696 

1443.8 

50. 

157.080 

1963.5 

K 

89.143 

632.36 

« 

111.919 

996.78 

H 

89.535 

637.9J 

H 

112.312 

1000.38 

43. 

135.088 

1452.2 

5^ 

89.928 

613.  .">."> 

B 

112.705 

1010.8 

K 

135.481 

1460.7 

347 


Table  28-58.    Fractional  Equivalents,  Powers  and  Roots  of  Numbers 


Num- 
ber 

Fric. 

equiv. 

Square 
root 

Cube 
root 

Square 

Cube 

6 

M 
O 
N 

> 

Num- 
ber 

Frac. 

equiv. 

Square 
root 

Cube 
root 

Square 

Cube 

i 

M 

0 

M 

.01 

.1 

.2154 

.0001 

.000001 

802 

.3281 

ii 

.5728 

.6897 

.1077 

.  03533 

4. 

594 

.0156 

A 

.125 

.25 

.  0002441 

.000003815 

1. 

003 

.33 

.5745 

.6910 

.1089 

.  03594 

4. 

607 

.02 

.1414 

.  2714 

.0004 

.  000008 

I. 

134 

34 

.5831 

.6980 

.1156 

.  03930 

1. 

677 

.03 

.1732 

.3107 

.0009 

.  000027 

1. 

389 

3438 

ii 

.5863 

.  7005 

.1182 

.  04062 

4. 

702 

.0313 

A 

.1768 

.3150 

.0009766 

.  00003052 

1. 

418 

.35 

.5916 

.  7047 

.1225 

.  04288 

4. 

745 

.04 

.2 

.3420 

.0016 

.  000064 

1 

601 

3594 

ii 

.5995 

.7110 

.1292 

.  04641 

t. 

808 

.0469 

A 

.2165 

.3606 

.002197 

.000103 

1 

756 

.36 

.6 

.7114 

.1296 

.  04666 

I. 

812 

.05 

.2236 

.  3684 

.0025 

.000125 

1. 

793 

.37 

.6083 

.7179 

.1369 

.  05065 

4. 

879 

.06 

.2449 

.3915 

.0036 

.  000216 

I. 

965 

.375 

yg 

.6124 

.7211 

.  1406 

.  05273 

4. 

911 

.  0625 

A 

.25 

.3968 

.  003906 

.  0002441 

2. 

005 

.38 

.6164 

.7243 

.1444 

.05487 

\. 

944 

.07 

.2646 

.4121 

.0049 

.000313 

2 

122 

.39 

.  6245 

.  7306 

.  1521 

.  05932 

5. 

009 

.0781 

A 

.2795 

.4275 

.006104 

.  0004768 

1  242 

.3906 

H 

.625 

.7310 

.1526 

.  05960 

5.013 

.08 

.2828 

.4309 

.0064 

.000512 

2 

269 

.4 

.6325 

.7368 

.16 

.64 

5. 

072 

.09 

.3 

.4481 

.0081 

.  000729 

2. 

406 

.4063 

ii 

.6374 

.  7406 

.1650 

.  06705 

5. 

112 

.0938 

A 

.3062 

.4543 

.  008789 

.0008210 

2. 

456 

.41 

.6403 

.7429 

.1681 

.  06892 

5. 

135 

.1 

.3162 

.4642 

.01 

.001 

2. 

537 

.42 

.6481 

.  7489 

.1764 

.  07409 

5. 

198 

.  1094 

jL 

.3307 

.4782 

.01196 

.  001308 

2 

653 

.4219 

ii 

.  6495 

.75 

.1780 

.  07508 

5. 

209 

.11 

.3317 

.4791 

.0121 

.001331 

2. 

660 

.43 

.  6557 

.7548 

.  1849 

.  07951 

5. 

259 

.12 

.3464 

.4932 

.0144 

.001728 

Z. 

778 

.4375 

A 

.6614 

.7591 

.1914 

.  08374 

5. 

305 

.125 

X 

.  3536 

.5 

.01562 

.  001953 

2. 

836 

.44 

.6633 

.7606 

.1936 

.08518 

5. 

320 

.13 

.3606 

.5066 

.0169 

.  002197 

2. 

892 

.45 

.6708 

.7663 

.  2025 

.09113 

5. 

380 

.14 

.3742 

.5193 

.0196 

.  002744 

3 

001 

.  4531 

1! 

.  6732 

.7681 

.  2053 

.  09304 

5. 

399 

.  1406 

A 

.375 

.  5200 

.  01978 

.  002781 

3. 

008 

.46 

.6782 

.7719 

.2116 

.  09734 

5. 

440 

.15 

.3873 

.5313 

.0225 

.  003375 

3 

106 

.  4688 

tt 

.6847 

.7768 

.2197 

.1030 

5. 

491 

.1563 

A 

.3953 

.  5386 

.  02441 

.003815 

3.170 

.47 

.6856 

.7775 

.2209 

.1038 

5. 

498 

.16 

.4 

.5429 

.0256 

.  004096 

3 

208 

.48 

.6928 

.7830 

.2304 

.1106 

5. 

557 

.17 

.4123 

.  5540 

.0289 

.004913 

3.307 

.4814 

ii 

.6960 

.7853 

.  2346 

.1136 

5. 

582 

.1719 

ii 

.4146 

.5560 

.  02954 

.  005077 

3 

325 

.49 

.7 

.  7884 

.  2401 

.1176 

5. 

614 

.18 

.4243 

.5646 

.0324 

.  005832 

3. 

403 

.5 

Vi 

.7071 

.7937 

.25 

.125 

5. 

671 

.1875 

A 

.433 

.5724 

.03516 

.  006592 

3 

473 

.51 

.7141 

.7990 

.2601 

.1327 

5.728 

.19 

.4359 

.5749 

.0361 

.  006859 

3. 

496 

.5156 

ii 

.7181 

.8019 

.2658 

.1371 

5. 

759 

.20 

.4472 

.5848 

.04 

.008 

3. 

587 

.52 

.7211 

.8042 

.2704 

.1406 

5. 

784 

.2031 

ii 

.4507 

.5878 

.  04126 

.  008381 

3. 

615 

.53 

.7280 

.8093 

.2809 

.  1489 

5. 

839 

.21 

.4583 

.5944!  .0441 

.  009261 

3 

675 

.  5313 

^2 

.7289 

.8099 

2822 

.1499 

5. 

846 

.2188 

A 

.4677 

.  6025 

.  04785 

.01047 

3 

751 

.54 

.7349 

.8143 

!2916 

.1575 

5. 

894 

.22 

.  4690 

.6037 

.0484 

.  01065 

3. 

762 

.  5  169 

ii 

.7395 

.8178 

.2991 

.1636 

5. 

931 

.23 

.4796 

.6127 

.0529 

.01217 

3. 

846 

.55 

.7416 

.8193 

.  3025 

.  1664 

5. 

948 

.2344 

if 

.4841 

.6165 

.  05493 

.01287 

3 

883 

.56 

.7483 

.  8243 

.3136 

.1756 

6. 

002 

.24 

.  4899 

.6215 

.0576 

.01382 

3 

929 

.  5625 

A 

.75 

.8255 

.3164 

.1780 

6. 

015 

.25 

ii 

.5 

.6300 

.0625 

.01563 

4. 

010 

.57 

.7550 

.8291 

.  3249 

.1852 

6.055 

.26 

.  5099 

.6383 

.0676 

.01758 

4. 

090 

.5781 

H 

.7603 

.  8330 

.3342 

.1932 

6. 

098 

.2656 

ii 

.5154 

.6428 

.  07056 

.01874 

4. 

134 

.58 

.7616 

.  83  10 

.  3364 

.  1951 

6.108 

.27 

.  5196 

.6463 

.0729 

.  01968 

4. 

167 

.59 

.7681 

.8387 

.  3481 

.2054 

6. 

161 

.28 

.5292 

.6542 

.0784 

.  02195 

4. 

244 

.  5938 

ii 

.7706 

.8405 

.3525 

.2093 

6. 

180 

.2813 

A 

.  5303 

.6552 

.  07910 

.  02225 

4. 

253 

.6 

.7746 

.8434 

.36 

.2160 

6. 

212 

.29 

.5385 

.6619 

.0841 

.  02439 

4. 

319 

.6091 

if 

.7806 

.  8478 

.3713 

.2263 

6. 

261 

.2969 

ii 

.5448 

.6671 

.  08814 

.02617 

4. 

370 

.61 

.7810 

.8481 

.3721 

.2270 

6. 

264 

.30 

.5477 

.  6694 

.09 

.027 

4. 

393 

.62 

.7874 

.8527 

.  3844 

.2383 

6. 

315 

.31 

.5568 

.6768 

.0961 

.02979 

4. 

466 

.625 

% 

.7906 

.  8550 

.  3906 

.2441 

6. 

341 

.3125 

A 

.5590 

.6786 

.  09766 

.  03052 

4. 

483 

.63 

.7937 

.  8573 

.3969 

.2500 

6. 

366 

.32 

.5657 

.  6840 

.1024 

.  03277 

4. 

537 

.64 

.8 

.8618 

.4096 

.2621 

6. 

416 

348 


Table  28-58.    Fractional  Equivalents,  Powers  and  Roots  of  Numbers — Continued 


Num- 
ber 

Frac. 

r.lil.' 

Square 
root 

Cube 
root 

Square 

Cube 

0 

M 

O 

M 
> 

Number 

Fric. 
«!«!«. 

Square 
root 

Cube 
root 

Square 

Cube 

\  2  G  x  No. 

.6-106 

n 

.800t 

.8621 

.4104 

.2629 

t. 

419 

.96 

.9798 

.9865 

.9216 

.8847 

7.858 

.65 

.8062 

.8662 

.4225 

.2716 

6. 

466 

.9688 

ii 

.9843 

.9895 

.9385 

.9091 

7.894 

.6563 

H 

.8101 

.8690 

.4307 

.2826 

'«, 

497 

.97 

.  9849 

.9899 

.9409 

.9127 

7  899 

.66 

.8121 

.8707 

.4356 

.  2875 

6 

516 

.98 

.9899 

.9933 

.  9604 

.9412 

7.940 

.67 

.8185 

.8750 

.  4489 

.  3008 

6 

565 

.9811 

H 

.9922 

.9918 

.9690 

.  9538 

7.957 

.6719 

it 

8197 

.8759 

.4511 

.  3033 

6 

574 

.99 

.9950 

.9967 

.9801 

.9703 

7.980 

.68 

«2I6 

.8794 

1621 

.3141 

6 

614 

1. 

1. 

1. 

8.021 

.'6875 

ii 

.8292 

.8826 

.4727 

.  3249 

6 

650 

.1 

•  • 

!OI9 

1  032 

1.21 

1  .  331 

8.412 

.69 

.8307 

.  8837 

.4761 

.  3285 

6 

662 

2 

.095 

1  .  063 

1.44 

1.728 

8.786 

.70 

.  8367 

8879 

.49 

.3130 

6 

710 

.3 

.14 

1.091 

1.69 

2.197 

9.145 

.7031 

ii 

.  8395 

8892 

.4944 

.3476 

6 

725 

.4 

.183 

1.119 

1  96 

2.744 

9.490 

.71 

.8t26 

.8921 

.5041 

.  3579 

6 

758 

.5 

1  .  225 

1.1145 

2.25 

3.375 

9.823 

.7188 

H 

8478 

.  8958 

.5166 

.3713 

6 

799 

1.6 

1  .  265 

1.170 

2.56 

4.096 

10  14 

.72 

.8485 

.8963 

.  5184 

.3732 

6 

805 

1.7 

>  t 

1  304 

1.193 

2  89 

4.913 

10.45 

.73 

.8544 

.9001 

.5329 

.  3890 

6 

853 

18 

1.342 

1.216 

3  24 

5  832 

10.76 

.7344 

ii 

.8570 

.9022 

.5393 

.  3961 

6 

873 

1.9 

1.378 

1.239 

3.61 

6.859 

11.06 

.74 

8602 

.9045 

.5476 

.  4052 

6 

899 

2. 

.. 

1.414 

1.260 

4. 

8. 

11.34 

.75 

*A 

.8660 

.9086 

.  5625 

.4219 

6 

946 

2.1 

.  . 

1.449 

1.281 

4.41 

9.261 

11  62 

.76 

.8718 

.9126 

.5776 

.4390 

6 

992 

2.2 

1.483 

1  301 

4.84 

10.65 

11.90 

7656 

H 

.875 

.9118 

.5862 

.4488 

7 

018 

2.3 

•  • 

1.517 

1.320 

5.29 

12.17 

12.16 

.77 

.8775 

.9166 

.  5929 

.4565 

7 

038 

2.4 

1.549 

1  339 

5.76 

13.82 

12.43 

.78 

.8832 

.9205 

.  6084 

.4746 

7 

083 

2.5 

1.581 

1.357 

6.25 

15.63 

12.68 

.7813 

tt 

.  8839 

.9210 

.  6104 

.4768 

7 

089 

2.6 

1.612 

1.375 

6.76 

17.58 

12.93 

.79 

.8888 

.9244 

.6241 

.  4930 

7 

129 

2.7 

1.643 

1.392 

7.29 

19.68 

13.18 

.7969 

ti 

.8927 

.9271 

.6350 

.  5060 

7 

159 

2.8 

1.673 

1.409 

7.84 

21  .  95 

13.42 

.8 

89  U 

.9283 

.64 

.5120 

7 

174 

2.9 

1.703 

1.426 

8.41 

24.39 

13.66 

.81 

.9 

.9322 

.6561 

.5314 

7 

218 

3. 

1.732 

1.442 

9. 

27. 

13  89 

.8125 

H 

.9014 

.9331 

.6602 

.5364 

7 

229 

3.1 

1.761 

1.458 

9.61 

29.79 

14.12 

.82 

.9055 

.9360 

.6724 

.5514 

7 

263 

3.2 

1.789 

1.474 

10.24 

32.77 

14.35 

.8281 

ii 

.9100 

.9391 

.6858 

.5679 

7 

298 

3.3 

1.817 

1.489 

10.89 

35  94 

14.57 

.83 

9110 

.9398 

.6889 

.5718 

7 

307 

3.4 

1  844 

1.504 

11.56 

39.30 

14  79 

.84 

.9165 

.9435 

.7056 

.5927 

7 

351 

3.5 

•  • 

1.871 

1.518 

12.25 

42.88 

15.01 

.8t38 

H 

.9186 

9449 

.7120 

.6007 

7 

367 

3.6 

1  897 

1.533 

12.96 

46.66 

15.22 

.85 

.9219 

.9473 

.  7225 

.6141 

7 

394 

3.7 

1.924 

1.547 

13.69 

50.65 

15.43 

.8594 

ii 

.9270 

.9507 

.7385 

.6347 

7 

.435 

3.8 

1.949 

1.560 

14  44 

54.87 

15.64 

.86 

.9274 

.9510 

.7396 

.6361 

7 

.438 

3.9 

1.975 

1.574 

15.21 

59.32 

15.85 

.87 

.9327 

.9546 

.7569 

.6585 

7 

.481 

4. 

2. 

1.587 

16. 

64. 

16.04 

.875 

% 

.9354 

.9565 

.7656 

.6699 

7 

.502 

4.1 

2.025 

1.601 

16.81 

68.92 

16.24 

.88 

9381 

.9583 

.7744 

.6815 

7 

.524 

4.2 

2.049 

1.613 

17.64 

74.09 

16.44 

.89 

.9434 

.9619 

.7921 

.7050 

7 

.566 

4.3 

2.074 

1.626 

18.49 

79.51 

16.63 

.8906 

H 

.9437 

.9621 

.7932 

.7065 

7 

.569 

4.4 

2.098 

1.639 

19.36 

85.18 

16  82 

.9 

.  9487 

.9655 

.81 

.7290 

7 

.609 

4.5 

2.121 

1.651 

20.25 

91.13 

17.01 

.9063 

ii 

.9520 

.9677 

.8213 

.7443 

7 

.635 

4.6 

2.145 

1.663 

21.16 

97.34 

17.20 

.91 

.9539 

.9691 

.8281 

.7536 

7.651 

4.7 

2.168 

1.675 

22.09 

103.8 

17.39 

.92 

.9592 

.9726 

.8464 

.7787 

7 

.693 

4.8 

2.191 

1.687 

23.04 

110.6 

17.57 

.9219 

ii 

.9601 

.9732 

.8499 

.  7835 

7 

.701 

4.9 

<  i 

2.214 

1.698 

24.01 

117.6 

17.75 

.93 

.9644 

.9761 

.8649 

.8044 

7 

.734 

5. 

.  . 

2.236 

1.710 

25. 

125. 

17.93 

.9375 

ii 

.9682 

.9787 

.8789 

.8211 

7.766 

.91 

.9695 

.9796 

.  8836 

.8306 

7 

.776 

.95 

,9747 

.9831 

.9025 

.8574 

7 

.817 

.9531 

ii 

.9763 

.9840 

.9084  .8659 

7 

.830 

349 


Table  28-59.     Comparison  of  Wire  Gauges 
Thickness  in  decimals  of  an  inch 


a 

• 

Gauge  No. 

American 
or  Brown  & 
Sharpe's 

Birmingham 
or  Stubs 

V 

i 

4 

.a 

• 

* 

! 

London  or 
Old  English 

United  States 
Standard 

d 
f. 

& 
j 

American 
or  Brown  & 
Sharpe's 

32 
%2 

Mm 

P  *- 

5  ° 
n 

• 
• 

4 
.d 

CO 

• 

I 

London  or 
Old  English 

United  States 
Standard 

0000000 

.490 

.500 

.5 

23 

.  02257 

.025 

.0258 

.024 

.027 

.028125 

000000 

.5800 

.460 

.464 

.  46875 

24 

.  02010 

.022 

.0230 

.022 

.025 

.025 

00000 

.5165 

.430 

.432 

.4375 

25 

.  01790 

.020 

.0204 

.020 

.023 

.  021875 

0000 

.4600 

.454 

.3938 

.400 

.454 

.  40625 

26 

.01594 

.018 

.0181 

.018 

.0205 

.01875 

000 

.4096 

.425 

.3625 

.372 

.425 

.375 

27 

.  01420 

.016 

.0173 

.  0164 

.0187 

.0171875 

00 

.3648 

.380 

.3310 

.348 

.380 

.  34375 

28 

.  01264 

.014 

.0162 

.0148 

.0165 

.015625 

0 

.3249 

.340 

.3065 

.324 

.340 

.3125 

29 

.01126 

.013 

.0150 

.0136 

.0155 

.  0140625 

1 

.2893 

.300 

.2830 

.300 

.300 

.  28125 

30 

.01003 

.012 

.0140 

.0124 

.01372 

.0125 

2 

.2576 

.284 

.2625 

.276 

.284 

.  265625 

31 

.  008928 

.010 

.0132 

.0116 

.0122 

.0109375 

3 

.2294 

.259 

.2437 

.252 

.259 

.25 

32 

.  007950 

.009 

.0128 

.0108 

.0112 

.01015625 

4 

.2043 

.238 

.2253 

.232 

.238 

.  234375 

33 

.  007080 

.008 

.0118 

.0100 

.0102 

.  009375 

5 

.1819 

.220 

.2070 

.212 

.22 

.21875 

34 

.  006305 

.007 

.0104 

.0092 

.  0095 

.  00859375 

6 

.1620 

.203 

.1920 

.192 

.203 

.  203125 

35 

.005615 

.005 

.  0095 

.  0084 

.0090 

.  0078125 

7 

.1443 

.180 

.1770 

.176 

.18 

.1875 

36 

.  005000 

.004 

.0090 

.0076 

.0075 

.  00703125 

8 

.1285 

.165 

.1620 

.160 

.165 

.171875 

37 

.  004453 

.0085 

.0068 

.  0065 

.  006640625 

9 

.1144 

.148 

.1483 

.144 

.148 

.  15625 

38 

.  003965 

.0080 

.0060 

.0057 

.  00625 

10 

.1019 

.134 

.1350 

.128 

.134 

.  140625 

39 

.  003531 

.0075 

.  0052 

.0050 

11 

.  09074 

.120 

.1205 

.116 

.12 

.125 

40 

.003145 

.0070 

.  0048 

.0045 

12 

.  08081 

.109 

.1055 

.104 

.109 

.  109375 

41 

.  002800 

.0044 

13 

.  07196 

.095 

.0915 

.092 

.095 

.  09375 

42 

.  002494 

.0040 

14 

.  06408 

.083 

.0800 

.080 

.083 

.  078125 

43 

002221 

.0036 

15 

.  05707 

.072 

.0720 

.072 

.072 

.  0703125 

44 

.  001978 

.0032 

16 

.05082 

.065 

.0625 

.064 

065 

.0625 

45 

.001761 

.0028 

17 

.  04526 

.058 

.0540 

.056 

.058 

.  05625 

46 

.001568 

.0024 

18 

.04030 

.049 

.0475 

.048 

.049 

.05 

47 

.001397 

.0020 

19 

.  03589 

.042 

.0410 

.040 

.040 

.  04375 

48 

.  001244 

.0016 

20 

.  03196 

.035 

.0348 

.036 

.035 

.0375 

49 

.001018 

.0012 

21 

.  02846 

.032 

.03175 

.032 

.0315 

.034375 

50 

.  0009863 

.0010 

22 

.  02535 

.028 

.0286 

.028 

.0295 

.  03125 

Table  28-60.     Useful  Factors 


Igal. 

1  gal  (British)  = 

1  cu.  ft.  = 

1  cu.  ft.  water  at  60  deg.  fahr.  = 

1  gal.  water  at  60  deg.  fahr.  : 

1  cu.  ft.  water  at  212  deg.  fahr.  = 

1  gal.  water  at  212  deg.  fahr.  = 

1  barrel  water  at  60  deg.  fahr.  = 

1  inch  mercury< 

I : 

1  Ib.  per  sq.  in.  pressure   = 
Height  of  a  column  of  water  in  feet  X  0.434   = 
A  column  of  water  1  sq.  in.  and  2}/$  ft.  high   = 
1  calorie   =  3.97  B.t.u. 
=  2.2046  Ib. 
=  B.t.u.  per  Ib. 
=  1.3405  hp. 
1  horsepower   =  0.746  kw. 

1  kilowatt!  =  56i9  B.t.u.  per  min. 


1  kilogram 

Calories  per  kilo  X  1.8 
1  kilowatt  (1000  watts) 


3414  B.t.u.  per  hour 


231  cu. in. 

0.13368  cu.  ft. 

277.274  cu.  in. 

7.4805  gal. 

62.37  Ib. 

8.34  Ib. 

59.76  Ib. 

7.99  Ib. 

31  V-i  gal.  =  262.7  Ib. 

iys  ft.  or  13.6  in.  water 

0.491  Ib.  per  sq.  in. 

2.304  ft.  water  at  60  deg.  fahr. 

Ib.  pressure  per  sq.  in. 

approximately  1  Ib. 

f  =  42.4  B.t.u.  per  min. 
1  mech.  horsepower!  =  2545  B.t.u.  per  hour 
[  =  33000  ft.  Ib.  per  min. 
1  boiler  horsepower   =  33479  B.t.u.  per  hour 

1  B.t.u.   =  778  ft.  Ib. 
1  ft.  Ib.  per  sec.   =  1.356  watts 


350 


Table  28-61.    Standard  Gauges  of  Sheet  Metal 


No.  of 
cause 

U.  S.  Standard 

Birmingham  or  Stubs 

Thickness,  inches 

Weight  per  sq.  ft.  in  Ib. 

Thickness,  inches 

Weight  per  sq.  ft.  in  Ib. 

No.  of 
gauge 

Fractions 

Decimals 

Iron 

Steel 

Fractions 

Decimals 

Iron 

Steel 

7-0 

1-2 

.5 

20.00 

20.4 

lApproz.) 

7-0 

6-0 

15-32 

.  46875 

18.75 

19.125 

6-0 

5-0 

7-16 

.4375 

17.50 

17.85 

5-0 

4-0 

13-32 

.40625 

16.25 

16.575 

29-64 

.454 

18.16 

18.52 

4-0 

3-0 

3-8 

.375 

15.00 

15.30 

27-64 

.425 

17.00 

17.34 

3-0 

2-0 

11-32 

.  34375 

13.75 

14.025 

3-8 

.38 

15.20 

15.50 

2-0 

0 

5-16 

.3125 

12.50 

12.75 

11-32 

.34 

13.60 

13.87 

0 

1 

9-32 

.28125 

11.25 

11.475 

19-64 

.3 

12.00 

12.24 

1 

o 

17-64 

.  265625 

10.625 

10.8375 

9-32 

.284 

11.36 

11.59 

2 

3 

1-4 

.25 

10. 

10.2 

17-64 

.259 

10.36 

10.57 

3 

4 

15-64 

.234375 

9.375 

9.5625 

15-64 

.238 

9.52 

9.71 

4 

5 

7-32 

.21875 

8  75 

8.925 

7-32 

.22 

8.80 

8  98 

5 

6 

13-64 

.203125 

8.125 

8.2875 

13-64 

.203 

8.12 

8.28 

6 

7 

3-16 

.1875 

7.5 

7  65 

3-16 

.18 

7.20 

7.34 

7 

8 

11-64 

.171875 

6  875 

7.0125 

.165 

6.60 

6.73 

8 

5-32 

9 

5-32 

.  15625 

6.25 

6.375 

.118 

5.92 

6.0t 

9 

10 

9-6  1 

.140625 

5.625 

5.7375 

9-64 

.134 

5.36 

5.47 

10 

11 

1-8 

.125 

5. 

5.1 

1-8 

.12 

4.80 

4.90 

11 

12 

7-6  1 

.  109375 

4.375 

4.4625 

7-64 

.109 

4.36 

4.45 

12 

13 

3-32 

.09375 

3.75 

3.825 

3-32 

.095 

3  80 

3.88 

13 

14 

5-61 

.078125 

3.125 

3.1875 

.083 

3.32 

3.39 

14 

15 

9-128 

.0703125 

2.8125 

2.86875 

5-64 

.072 

2.88 

2.91 

15 

16 

1-16 

.0625 

2.5 

2.55 

1-16 

.065 

2.60 

2.65 

16 

17 

9-160 

.  05625 

2.25 

2.295 

.058 

2.32 

2.37 

17 

18 

1-20 

.05 

2 

2.04 

.049 

1.96 

2.00 

18 

3-64 

19 

7-160 

.04375 

.  75 

1.785 

.042 

.68 

1.71 

19 

20 

3-80 

.0375 

.50 

1.53 

.035 

.40 

1.43 

20 

21 

11-320 

.  034375 

.375 

1  .  4025 

1-32 

.032 

.28 

1.31 

21 

22 

1-32 

.03125 

.25 

i  L>7.-> 

.028 

.12 

1.14 

22 

23 

9-320 

.  028125 

.125 

1.1475 

.025 

00 

1.02 

23 

24 

1-40 

025 

1.02 

.022 

.88 

.90 

24 

25 

7-320 

.  021875 

!875 

.8925 

.02 

.80 

.82 

25 

26 

3-160 

.01875 

.75 

.765 

.018 

.72 

.73 

26 

27 

11-6  tO 

.0171875 

.6875 

.70125 

1-64 

.016 

.64 

.65 

27 

28 

1-64 

.  015625 

.625 

.6375 

.014 

.56 

.57 

28 

29 

9-640 

.0110625 

.5625 

.  57375 

.013 

.52 

.53 

29 

30 

1-80 

.0125 

.5 

.51 

.012 

.48 

.49 

30 

31 

7-640 

.0109375 

.4375 

.44625 

.01 

.40 

.41 

31 

32 

13-1280 

.01015625 

.40625 

.414375 

.009 

.36 

.37 

32 

33 

3-320 

.009375 

.375 

.3825 

.008 

.32 

.33 

33 

34 

11-1280 

.  00859375 

.34375 

.  350625 

.007 

.28 

.29 

34 

35 

5-640 

.0078125 

.3125 

.31875 

.005 

.20 

.20 

35 

36 

9-1280 

.  00703125 

.28125 

.286875 

.004 

.16 

.16 

36 

37 

17-2560 

.  00664062 

.265625 

.2709375 

37 

38 

1-160 

.  00625 

.25 

.255 

38 

Table  28-62.     Measures  of  Weight,  Contents  and  Area 


Long  Measure 


Square  Measure 


12  inches  =  1  foot. 

3  feet  =  1  yard. 
5J/6  yards  =  1  rod. 

4  rods  =  1  chum. 

10  chains  =  1  furlong. 
8  furlongs  =  1  mile. 

Liquid  Measure 

4  gills  =  1  pint.  31  V£  gallons  =  1  barrel. 

2  pints  =  1  quart.  2  barrels  =  1  hogshead. 

4  quarts  =  1  gallon. 


144  square  inches  =  1  square  foot. 
9  square  feet  =  1  square  yard. 
30 J4  square  yards  =  1  square  rod. 
160  square  rods  =  l  acre. 
640  acres  =  1  square  mile. 


Cubic  Measure 

1728  cubic  inches  =  1  cubic  foot. 
27  cubic  feet  =  1  cubic  yard. 
24.75  cubic  feet  =  1  perch. 
128  cubic  feet  =  1  cord. 


Avoirdupois  Weight 
16  ounces  =  1  pound. 
100  pounds  =  1  hundredweight. 
20  cwt.  =  1  ton. 


351 


Table  28-63.    Mensuration  of  Surfaces  and  Volumes 

Area  of  rectangle  =  length  X  breadth. 
Area  of  triangle  =  base  X  Yi  perpendicular  height. 
Diameter  of  circle  =  radius  X  2. 
Circumference  of  circle  =  diameter  X  3.1416. 
Area  of  circle  =  square  of  diameter  X  .7854. 

area  of  circle  X  number  of  degrees  in  arc. 

Area  of  sector  of  circle  =  

360 

Area  of  surface  of  cylinder  =  circumference  X  length  +  area  of  two  ends. 

To  find  the  diameter  of  circle  having  given  area:    Divide  the  area  by  .7854,  and  extract  the  square  root. 

To  find  the  volume  of  a  cylinder:    Multiply  the  area  of  the  section  in  square  inches  by  the  length  in  inches 

=  the  volume  in  cubic  inches.    Cubic  inches  -H  1728  =  volume  in  cubic  feet. 
Surface  of  a  sphere  =  square  of  diameter  X  3.1416. 
Solidity  of  a  sphere  =  cube  of  diameter  X  .5236. 
Side  of  an  inscribed  cube  =  radius  of  a  sphere  X  1.1547. 
Area  of  the  base  of  a  pyramid  or  cone,  whether  round  square  or  triangular,  multiplied  by  one-third  of  its 

height  =  the  solidity. 
Diam.  X  .8862  =  side  of  an  equal  square. 

Diam.  X  .7071  =  side  of  an  inscribed  square.  T  =  proportion  of  circumference  to 

Radius  X  6.2832  =  circumference.  diameter  =  3.1415926. 

Circumference  =  3.5446  X  V  area  of  circle.  ^'  =  9.8696044. 

Diameter  =  1.1283  X  V  area  of  circle.  ^  =  1-7724538. 

Length  of  arc  =  no.  of  degrees  X  .017453  radius.  Log.     T  =  0.49715. 

Degrees  in  arc  whose  length  equals  radius  =  57°  2958'.  I/T  =  0.31831. 

Length  of  an  arc  of  1  deg.  =  radius  X  .017543.  1/360  =  .002778. 

Length  of  an  arc  of  1  min.  =  radius  X  .0002909.  360/^  =  114.59. 

length  of  an  arc  of  1  sec.  =  radius  X  .0000048. 


Table  28-64.     Electrical  Units 

Volt — The  unit  of  electrical  motive  force.     Force  required  to  send  one  ampere  of  current  through  one  ohm 

of  resistance. 

Ohm — Unit  of  resistance.     The  resistance  offered  to  the  passage  of  one  ampere,  when  impelled  by  one  volt. 
Ampere — Unit  of  current.     The  current  which  one  volt  can  send  through  a  resistance  of  one  ohm. 
Coulomb — Unit  of  quantity.     Quantity  of  current  which,  impelled  by  one  volt,  would  pass  through  one  ohm 

in  one  second. 
Farad — Unit  of  capacity.     A  conductor  or  condenser  which  will  hold  one  coulomb  under  the  pressure  of  one 

volt. 

Joule — Unit  of  work.     The  work  done  by  one  watt  in  one  second. 
Watt — The  unit  of  electrical  energy,  and  is  the  product  of  ampere  and  volt.     That  is,  one  ampere  of  current 

flowing  under  a  pressure  of  one  volt  gives  one  watt  of  energy. 
One  electrical  horsepower  is  equal  to  746  watts. 
One  kilowatt  is  equal  to  1,000  watts. 
To  find  the  watts  consumed  in  a  given  electrical  circuit,  such  as  a  pump  motor,  multiply  the  volts  by  the 

amperes. 

To  find  the  volts,  divide  the  watts  by  the  amperes. 
To  find  the  amperes,  divide  the  watts  by  the  volts. 

To  find  the  electrical  horsepower  required  by  a  motor,  divide  the  watts  of  the  motor  by  746. 
To  find  the  mechanical  horsepower  necessary  to  generate  the  required  electrical  horsepower,  divide  the  latter 

by  the  efficiency  of  the  generator. 
To  find  the  amperes  of  a  given  circuit,  of  which  the  volts  and  ohms  resistance  are  known,  divide  the  volts  by 

the  ohms. 

To  find  the  volts,  when  the  amperes  and  ohms  are  known,  multiply  the  amperes  by  the  ohms. 
To  find  the  resistance  in  ohms,  when  the  volts  and  amperes  are  known,  divide  the  volts  by  the  amperes. 


Table  28-71.    Conversion  of  Fahrenheit  and  Centigrade  Temperatures 

9  5 

Formulae:  fahr.  =  -=-  cent.  +  32  deg.  cent.  -*_  (fahr.  —  32  deg.) 

9 


FAHR. 

CENT. 

FAHR. 

CENT. 

FAHR. 

CENT. 

FAHR. 

CENT. 

• 

— 

40 







"150 

10  — 



110 

210  — 



310:  = 

— 

212  — 

100 

—10 

Boiling 

20  = 

— 

120 

— 

220 

— 

320  = 

160 

— 

50 

— 

— 

— 

— 

— 

in~~' 

— 

1  ^n 

— 

7^0 

~  1  10 

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General  Index 


See  also  the  following  additional  indexes:  Tables,  page  362;  Webster  Service 
Details,  page  364;  Webster  Apparatus,  page  366. 


Accumulator,  water  (see  water  accumulator) . . . 

Acid,  tartaric,  manufacture  of 196 

Air,  capacity  of  various  sizes  of  pipes,  (table) ...   69 

ducts,  area  of,  for  indirect  radiators 54 

ducts,  method  of  sizing 68 

ducts,  sized  by  friction  loss  method 68-69 

ducts,  sized  by  velocity  method 68 

elimination,     importance     of,     in     dry     kiln 

coils 181, 186 

heat     required     to     raise     temperature     of, 

(tables) 72,  73 

infiltration 31-33 

infiltration,  B.  t.u.  required  for,  (table) 33 

infiltration,  double-hung  windows,  (chart) ....   32 

infiltration,  example  of 33 

infiltration,  experiment  on 32 

pressure  loss  in  ducts,  (chart) 70 

properties  of,  (table) 331 

quantities  required  for  ventilation,  (table) ....   67 

recirculation  of,  in  industrial  plants 67 

removal  devices,  modulation  system 162 

removal  from  coils  in  dry  kilns 184 

resistance  of  elbows,  (table) 71 

-separating  tanks,  description  and  dimensions 

of 264-266 

-separating  tanks,  discharge  of  returns  through,144 
-separating  tanks,  plain,  method  of  connecting 

returns  from  vacuum  pump 144 

-separating  tanks,  water-control,  method  of 
connection  to  vacuum  pump  and  to  feed- 
water  heater 145 

supply,  cold,  for  schools 61 

supply  for  class  rooms 61 

supply,  proper 60 

velocities  for  fan  system,  public  buildings ....  67 
velocities  for  fan  systems,  various  types  of 

buildings,  (table) 68 

Altitude,   effect  upon   boiling   point  of  water, 

(table) 332 

effect  iijKjii  design  of  chimney 87 

Anchor  points,  allowable  distance  between 283 

Anthracite  coal,  heat  values  of,  (tables) . . .  340,  341 
Apartment  buildings,  considerations  leading  to 
selection  of  type  of  heating  system  for. . .  97,  109 

operating  pressure 239 

Architectural  features,  effect  upon  selection  of 

type  of  heating  system 103 

Area,  measures  of,  (table) 351 

Areas  of  circles,  (table) 346-347 

Attachments  for  Sylphon  traps  (see  Trap  attach- 
ments) 

Auditoriums,  ventilation  of 63 

Automatic  pump  and  receiver,  connections  for 

discharge  from  vacuum  pump 149 

Avoirdupois  weights,  (table) 351 

Bain  marie  (see  Kitchen  equipment) 

Ball  check  valves  (see  Modulation  vent  valves) 

Banquet  hall,  ventilation  of 64 

Basement  radiation,  method  of  draining,  modu- 
lation system 229,  232 

Belt  driven  vacuum  pumps 143 

Bends,  effect  of,  upon  flow  of  steam  through 

pipes,  (table) 115 

Bituminous  coal,  heat  values  of,  (table) 339-340 


Blanket  warmers  (see  Hospital  equipment) 

Blast  heaters,  connections  for 225-227 

Blower  sections,  connections  for 225-227 

Boiler  feed  pump  and  receiver,  connections  for 

discharge  from  vacuum  pump 149 

feed  pump  controlled  by  air-separating  tank, 

connections  for 149 

feeder,  connections  with  double-control  hydro- 
pneumatic  tank  and  geared-type  vacuum 

pump ...._.._. 147 

feeder,  description  and  dimensions  of 274 

rooms,  size  of 94,  108 

tubes,  dimensions  of,  (table) 317 

Boilers,  basis  for  rating 89 

cast  iron  type 106 

efficiency  of 91 

high-pressure,    as    used    in    connection    with 

vacuum  systems 107 

method  for  cleaning 93 

modulation   system  connections  for   thermo- 
static  and  for  time  clock  control  of  damper 

regulator 231 

modulation   system   connections  for   parallel 

operation 230 

necessity  for  withstanding  corrosion  in 106 

priming  of 93,  105 

proportions  of 90 

required  firing  periods  for 93 

return  tubular,  dimensions  of,  (table) 330 

selection  of  proper  type  of 105-108 

water  space  of 90 

Boiling   point  of  water  at   various    altitudes, 

(table) 332 

Botanical  gardens  (see  Greenhouses) 

Brass  tubes,  diameters  and  lengths  of,  (table) ...  315 

British  thermal  unit,  definition  of 9 

Building,  size  and  type  of,  for  determining  choice 
of  heating  system 97 

Calorific  values  of  coal 340 

Candy,  manufacture  of 196 

Capacity,  air-carrying,  of  various  sizes  of  pipes, 

(table) 69 

definition  of 233 

Carpenter,  Prof.  R.  C.. 112 

Ceilings,  heat  transmission  factors  for 30 

Centrigrade,  conversion  to  fahrenheit  scale. . .  .353 

Centra]  station  heat 107 

Check  valves,  special,  for  modulation  systems, 

application  details  of 268,  269 

Chemical  plants,  exhaust  ventilation  for 65-66 

Chimney  lining,  dimensions  of  standard  sizes  of. .  75 

Chimneys,  effect  of  altitude  upon  design  of 87 

for  house  heating  boilers 74 

capacity  of,  (table) 76-77 

linings  for,  (table) 75 

proportioning  of 74 

for  power  boilers 78 

procedure  for  proportioning 79 

Churches,  considerations  leading  to  selection  of 

type  of  heating  system  for 100 

ventilation  of 63 

Circles,  circumferences  and  areas  of,  (table)  .346-347 

Clearance,  vacuum  pumps 139 

Cloth-drying  machines,  application  of  Webster 
apparatus  to 190 


354 


General  Index — Continued 


Cloth-drving  machines,  description  of 190 

Coal,  anthracite,  heat  values  of,  (table)  .  .  .  .310-341 

bituminous,  heat  values  of,  (table) 339-340 

calorific  value  of,  (table) 340 

grate  areas  required  for  burning,  (table) 92 

rates  of  combustion  of,  (table) 92 

Coals,  classification  of 339-340 

Coffee  urns  (see  Kitchen  equipment) 

Coils,  continuous  header  type,  in  dry  kilns 182 

design  of,  for  lumber  dry  kilns 183 

drainage  of 220-221 

pipe,  limit  of  length  of 43 

pipe,  surface  in  square  feet  of,  (table) 56-57 

sectional  header  type  in  dry  kilns 184 

vertical  header  type  in  dry  kilns 185 

Cold  air  ducts,  area  of,  for  indirect  radiation ...   54 

Combination  gauges 267 

connections  for 268 

Combination  systems,  vacuum  and  modulation.  100 

Combustion  rates  for  various  coals,  (table) 92 

Computation  sheets  for  example  of  factory  heat 

requirements 40—41 

Computation  sheets  for  example  of  residence  heat 

requirements 38-39 

Computations,   for   direct   and   indirect  radia- 
tion  55-58 

for  indirect  radiation 53-54 

Condensation,  losses  in  steam  piping 113 

products  of 12 

saving  due  to  return  to  boilers.    13 

Condensed  milk  (see  Condensories) 

Condensing  engines,  bleeding  receiver  of 175 

Condensories,  application  of  Webster  system  to. .  196 

Connections,  details  of,  to  indirect  radiator 52 

offset,  (table) 319 

Conserving  system,  description  of 173 

typical  layout  of 173 

Conserving  valves,  description  and  dimensions  of.  273 

illustration  of 174 

Contents,  measures  of,  (table) 351 

of  round  tanks,  (table) 335 

Controllers,  Hylo  (see  Hylo  controllers) 
Cooking,   steam    appliances    for    (see    Kitchen 

equipment) 

Copper  tubes,  diameters  and  lengths  of,  (table) .  315 
Costs  of  direct  cast  iron  radiation,  relative .  .  .  .51-52 

Critical  velocities  in  radiator  run-outs 132-134 

Critical  velocity,  definition  of 132 

Cube  roots  of  numbers,  (table) 348-349 

Cubic  measure,  (table) 351 

Damper  control  for  boilers 94 

Damper  regulators,  description  and  dimensions  of  .271 
method  of  control  by  thermostat  and  by  time 

clock 231 

use  in  connection  with  conserving  valve 175 

Dampers,  air  volume,  at  branch  ducts 72 

Data  required  for  design  of  steam  heating  sys- 
tems    15 

Decimal  equivalents  of  fractions,  (table) .  .  .348-349 

equivalents  of  inches,  (table) 344-345 

Densities  of  materials,  (table) 342 

DiOWential-type  return  trap,  description  of . . .  .155 
Differential  pressures  through  traps  and  valves  .238 

Direct  radiation,  definition  of 11 

example  of  computation  of 55,  58 

heat  emission,  (table) 45 

heat  emission  with  varying  room  temperature.  47 
heat  emission  with  varying  steam  pressure. . .  46 

relative  costs  of  cast  iron,  (table) 51-52 

with  exhaust  systems 66 

Direct-indirect  radiators,  data  for 55 


Direct-indirect  radiators,  description  of 55 

Direct-indirect  system  of  ventilation 60 

Dirt,  effect  of,  on  size  of  return  mains 13 

Dirt  strainers,  description  of 259 

dimensions  of 260 

Disposal  of  condensation  in  vacuum  systems .  .  .  171 

Doors,  heat  transmission  factors  for 28 

Double-control  hydro-pneumatic  tanks,  descrip- 
tion and  dimensions  of 276-277 

used  in  connection  with  geared-type  vacuum 

pump  and  boiler  feeder 147 

Double-service  valves 164 

description  and  dimensions  of 252-254 

ratings  of 237 

typical  installation  detail  of 253 

Down-feed  riser,  definition  of 12 

draining  through  radiator 220,  253 

Down-feed  systems,  modulation 163 

vacuum 167-168 

Draft,  chimney,  definition  of 78 

intensity  of,  (formula) 79 

losses 80 

losses  in  boiler,  (formula) 84 

losses  in  flues,  (formula) 83 

losses  in  furnace,  (formula) 84 

losses  in  stack,  (formula) 81 

required  for  various  fuels,  (chart) 85 

Drag  lifts 263 

Dry  kilns 179 

causes  of  trouble  in 181 

design  of  pipe  coils  for 183 

important  features  of  design  of 181 

plans  showing  use  of  continous-header  coil  in .  182 
plans  showing  use  of  sectional-header  coil  in . .  184 
plans  showing  use  of  vertical-header  coil  in. . .  185 

temperature  with  exhaust  steam  in 181 

temperature  with  live  steam  in 183 

use  of  exhaust  steam  in 181 

Dry  returns,  methods  of  connections  for  modu- 
lation systems 228-229 

modulation  systems 162,  164 

Drying,  cloth 190 

improper  methods  of  lumber 179 

paper 192 

yarn 188 

Ducts,  air-carrying,  capacity  of  various  sizes  of, 

(table) 69 

air  pressure  loss  in,  (chart) 70 

area  of,  for  indirect  radiation 54 

comparison  of  friction  in  round  and  rectangular  71 

hot-air,  with  hot  blast  system 66 

method  of  sizing 68 

resistance  of  air  in  elbows  of,  (table) 71 

trunk    line    system,    sized    by    friction    loss 

method 68-69 

trunk  line  system,  sized  by  velocity  method . .  68 
underground  masonry,  for  schools 62 

Economizer,  vapor,  and  suction  strainer,  des- 
cription and  dimensions  of 261—262 

Economy,  feed- water  heaters,  (table) 301 

Economy  of  returning  condensation  to  boiler ...   13 
Efficiency,  increase  in,  for  radiation  with  shield.   51 

decrease  in,  with  enclosed  radiators 50 

heating  tests  of  return  traps  for 154 

Elbows,  friction  of  water  in,  (table) 336 

resistance  of  air  in,  (table) 71 

Electrical  units,  definitions  of 352 

Electric-driven  vacuum  pumps 137,  172 

for  vacuum  systems  using  low-pressure  boilers.  173 
use  of,  in  schools,  churches,  etc.,  for  inter- 
mittent heating 100 


3H 


General  Index — Continued 


Enclosed  radiator,  with  grilles  ................  49 

decreased  efficiency  of,  (table)  ..............  50 

Enclosure  for  radiators  ......................   48 

Engine,  horsepower  of  ......................  329 

Evaporation,  boiler,  measurement  of  ..........  313 

Expansion,  joints,  allowable  distances  between 
anchor  points  of  ........................  283 

joints,  description  and  dimensions  of  ....  278—282 

loops  in  risers  ............................  216 

of  solids,  lineal,  (table)  ....................  344 

of  wrought  iron  pipe,  (table)  ...............  318 

Exposure  and  protective  conditions  ...........   15 

Extra-heavy  fittings,  dimensions  of,  (table),  324—  327 
flanges,  dimensions  of,  (table)  ..............  324 

iron  pipe,  dimensions  of,  (table)  ............  317 

Factories,  removal  of  fumes  or  dust  in  ........  65 

Factors,  basic,  for  heat  transmission  ...........  25 

Factory,  examples  of  computation  sheet  of  heat 
requirements  for  ......................  40-41 

plan  showing  heat  requirements  for  .........  37 

Fans,  sizes  and  arrangement  of  ...............  72 

Feeder,  boiler  (see  Boiler  feeder) 

Feed-water  heater,  gravity  return  to  ..........  222 

economy  of,  (chart)  .......................  301 

steam-control  type,  typical  connections  to  ....  304 

water-control  type,  typical  connections  to.  ...  303 

Webster,  description  of  ................  302-313 

dimensions,  Class  EB  ....................  310 

dimensions,  Class  EBP  ..................  311 

dimensions,  Class  EF  ....................  313 

dimensions,  Class  EFP  ..................  312 

Fire  protection  for  exposed  water  hydrants  .....  195 

Fireplace  ...................................  60 

Fittings,    cast    iron,    screwed,    dimensions    of, 
(table)  .................................  319 

effect  of,  upon  steam  flow  ..................  115 

extra-heavyflanged.dimensionsof,  (table)  .324-327 
extra-heavy  flanged,  rules  for  ...............  324 

lift  (see  Lift  fittings) 

standard  flanged,  dimensions  of,  (table)  .  .  320-323 

standard  flanged,  rules  for  ..................  320 

Flanges,  extra-heavy,  dimensions  of,  (table)  ....  324 

standard,  dimensions  of,  (table)  .............  320 

Float-type  return  trap,  description  of  ..........  154 

Floors,  above  cold  space,  heat  transmission  fac- 
tors for  ................................  29 

laid  on  ground,  heat  transmission  factors  for.  .  30 
Flow  of  steam  through  pipes  .................  110 

Flow  of  water,  through  elbows,  (table)  .........  336 

through  pipes,  (table)  .....................  337 

Flues,  chimney  (see  Chimney  flues) 

Food  products,  manufacture  of  ...............  204 

Fractional  equivalents  of  decimals,  (table)  .348-349 
Friction,  air  in  ducts,  (chart)  ...........  .  .....  70 

round  and  rectangular  ducts,  comparison  of 
losses,  (chart)  ..........................  71 

steam  in  pipes  ............................  Ill 

water  in  elbows,  (table)  ..........  ..........  336 

water  in  pipes,  (table)  .....................  337 

Fuel  saving  by  preheating  feed  water  ..........  301 

Fuels,  draft  required  for  different,  (chart)  ......  85 

Fumes,  removal  of  ..........................  65 

Furnaces  for  steam  boilers  ...................  90 


water,  weight  at  various  temperatures 
of,  (table)  ..............................  335 

Gauges  (see  Combination  gauges) 
combination  (see  Combination  gauges) 
Hylo.  ................  .  ..................  178 

sheet  metal,  (table)  .......................  351 

typical  connections  of  .....................  150 


Gauges,  wire,  comparison  of,  (table) 350 

Geared-type  vacuum  pump 146 

connections  with  boiler  feeder  and  double-con- 
trol hydro-pneumatic  tank 147 

with  single-control  hydro-pneumatic  tank ....  146 
Generator,  hot-water  (see  Hot-water  generator) 

Glass,  roof,  heat  transmission  factors  for 29 

Governor,   vacuum  pump   (see  Vacuum  pump 
governor) 

typical  connections  for 151 

Grade  of  pipe,  effect  upon  critical  velocity  of . . .  133 
Grate  surfaces  for  various  grades  of  coal,  (table) .  92 

Grates  for  steam  boilers 90 

Gravity,  indirect  radiation,  definition  of 11 

drips,  hydraulic  head  for 119 

Grease  traps,  description  of 257 

dimensions  of 258 

method  of  connecting,  for  draining  of  oil  sepa- 
rator   255 

Greenhouses,  application  of  Webster  systems  to. 205 
Grille  enclosure  for  radiators 49 

Heads    of   water   corresponding    to   pressures, 

(table) 333 

Heat  absorbing  capacity  of  materials 19 

absorption  by  stored  materials 10 

content 9 

emission  of  direct  radiation,  (table) 45 

percentage  of  variation  of,  (chart) 44 

with  varying  room  temperatures,  (chart) ....  47 

with  varying  steam  pressures,  (chart) 46 

head 21 

location  and  character  of  source  of 15 

loss  required  for  air  infiltration,  (table) 33 

losses  through  monitors 24 

required  to  raise  temperature  of  air,  (tables)72,  73 

requirements 10 

computation  sheet  for  factory 40-41 

computation  sheet  for  residence 38-39 

example  of  factory 36 

example  of  residence 35 

for  stored  materials 35 

method  of  calculating 34 

plan  of  factory 37 

where  heating  is  not  continuous 35 

specific,  definition  of 9 

stratification,  illustration  of 23 

transmission,  basic  factors  for 25 

transmission  factors,  ceilings 30 

doors 28 

floors  above  cold  space 29 

floors  laid  on  ground 30 

interior  walls 25 

roof  construction 28 

roof  glass  and  skylights 29 

walls,  brick 26 

walls,  clapboard 25 

walls,  concrete  faced  with  brick 26 

walls,  concrete  faced  with  stone 27 

walls,  corrugated  iron 26 

walls,  hard  stone  or  concrete 27 

walls,  hollow  tile 27 

walls,  hollow  tile  faced  with  brick 26 

walls,  sandstone  or  limestone 27 

walls,  stucco  on  studs 26 

windows 28 

windows  above  datum 28 

wood_  partitions 28 

transmission  rates,  fundamental  conditions. . .  21 

transmitted  through  steam  pipes 116 

units,  definitions  of 9 

values  of  various  kinds  of  coal,  (table) . . .  339-341 


356 


General  Index — Continued 


Heater-meter,  Webster-Lea,  description  of.  313-314 
Heaters,  blast  (see  Blast  heaters) 

feed-water  (see  also  Feed-water  heaters) 
feed-water,    connections    from    water-control 

air-separating  tank 145 

method  of  calculating  size  of 72 

Heating,  initial 9 

Heating  efficiency,  tests  of  return  traps  for 154 

surface  of  pipe  coils,  (table) 56-57 

surface,  boiler 90 

surface,  character  and  location  of 19 

surface,  method  of  computing  and  selecting. . .  42 
systems,   basic  data  required  for  the  design 

of 15 

systems,  hot  blast 66 

Heavy-duty  traps,  connection  for  coils  drained 

through  one  trap  in  lumber  dry  kilns 187 

high-differential  type,  application  to  drainage 

of  vacuum  pan 201 

high-differential  type,  description  and  dimen- 
sions of 249 

method  of  running  return  pipe  in  lumber  dry 

kilns 187 

sectional  drawing  of 225 

Series  19T,  description  of 247 

Series  19T,  dimensions  of 249 

Series  19T,  ratings  of 239 

use  in  lumber  dry  kilns 182,  186 

High-differential  heavy-duty  traps  (see  Heavy- 
duty  high  differential  traps) 

High-duty  vent  trap 163 

application  of 120 

High-pressure  Sylphon  traps,  application  for  hos- 
pital equipment 202 

application  for  kitchen  equipment 203 

application  to  hydrants  to  prevent  freezing. .  .195 

description  and  dimensions  of 275 

typical  installation  for  railroad  switches 194 

Horsepower,  boiler 89 

of  an  engine 329 

of  return  tubular  boilers,  (table) 330 

Hospital  equipment,  application  of  Webster  sys- 
tems to 202 

Hospitals,   considerations  leading  to  choice  of 

type  of  heating  system  for 107 

Hot  air  ducts,  area  of,  for  indirect  radiation ....  54 
Hot  blast  heating  system  for  industrial  plant.s .  .   66 

Hot  water  generator,  connections  for 

222,  227,  229 

Hot  water  pattern  radiation,  connections  for ...  43 
Hotels,  considerations  leading  to  selection  of  type 

of  heating  system  for 106 

Humidity 59 

relative  indoor 19 

Hydraulic  head  for  gravity  drips 119 

Hydro-pneumatic  tanks,  description  and  dimen- 
sions of 276-277 

discharge  to 147 

double-control,  connections  with  geared-type 

vacuum  pump  and  boiler  feeder 147 

selection  of  size  of 138,  142 

single-control,   connections   with   geared-type 

vacuum  pump 146 

Hylo  controllers 178 

controllers,  dimensions  of 272 

gauges 178 

systems,  typical  connections  of  special  appa- 
ratus  177 

traps 178 

traps,  dimensions  of 272 

vacuum  systems,  description  of 176 


Impurities,  lack  of,  in  distilled  water 13 

in  condensation 12 

Indirect  radiation,  connection  for  air  supply  of.   65 

definition  of 11 

example  of  computation  of 55-58 

formula  for  computing 54 

method  of  computing 53-54 

methods  of  heating  by 53 

with  exhaust  systems 66 

Indirect  radiator,  details  of  connection  to 52 

Indirect  stacks,  connections  for 225-227 

Indirect  system  of  gravity  ventilation 60 

Industrial  plants,  exhaust  ventilation  for 65 

hot  blast  systems  for 66 

Infiltration,  air 31 

B.t.u.  required  for,  (table) 33 

double-hung  windows,  (chart) 32 

example  of 33 

Initial  heating  period 10 

Initial  velocity  of  steam  flow,  (table) 110 

Inleakage  of  air  to  piping  of  vacuum  system, 

effect  of 122 

Inside  temperature  requirements,  (table) 18 

Intermittent  use  of  building,  effect  upon  design 

of  heating  system 100 

Iron  pipe,  dimensions  of,  (table) 316-317 

Joints,  expansion  (see  Expansion  joints) 

Kettles,  cooking  (see  Kitchen  equipment) 

Kilns,  lumber  drying 179 

causes  of  trouble  in 181 

construction  of 180 

design  of  pipe  coils  for 183 

important  features  in  design  of 181 

plans  showing  use  of  continuous  header  coils  in.182 
plans  showing  use  of  sectional  header  coils  in .  183 
plans  showing  use  of  vertical  header  coils  in. .  185 

Kitchen,  heating  equipment  for 106 

heating   equipment,    application   of  Webster 

systems  to 203 

ventilating  equipment  for 64 

Laboratory  tests  of  return  traps 153 

Lift  fittings,  application  for  "step-up"  lifts 139 

Series  20,  description  of 263 

Series  20,  dimensions  of 264 

typical  application  of 263 

Lift  pockets  (see  Lift  fittings) 

Lifts,  drag 263 

method  of  design  for  "step-up" 139 

Liquid  measure,  (table) 351 

Location  of  building,   effect  upon  selection  of 

design  of  heating  system 101 

Lock-shield  modulation  valves 170 

Long  measure,  (table) 351 

Loss,  friction,  in  round  and  rectangular  ducts, 

(chart) 71 

Lubricator,  force-feed 170 

sight-feed 170 

sight-feed,  typical  connections  of 151 

Lumber-drying,  improper  methods  of 179 

kilns 179 

kilns,  causes  of  trouble  in 181 

kilns,  important  features  in  design  of 181 

processes 179 

tests 180 

Machinery,  heat-absorbing  capacity  of 19 

Mains,  dripping,  in  vacuum  system 167 

method  of  dripping 215 

ratings  for  vacuum  and  modulation  return  128-129 


357 


General  Index — Continued 


Mains,    ratings    for    vacuum    and    modulation 

supply 128-129 

steam  (see  Risers) 

supply  and  return,  definition  of 12 

Material,  densities  of,  (table) 342-343 

specific  heats  of,  (table) 342 

tensile  strength  of,  (table) 343 

weights  of,  (table) 341 

Measures  of  pressure,  comparison  of,  (table) ....  334 

Mechanical  indirect  radiation,  definition  of 11 

Mechanical  laboratory,  illustration  of 152 

Meeting  rooms,  ventilation  of 64 

Mensuration  of  surfaces  and  volumes 352 

Meter-heater  (see  Heater-meter) 
Milk  condensories  (see  Condensories) 

Modulation  system,  advantages  of 109 

basement,  radiators  for 162 

classes  of  structures  for  application  of 96 

descriptions  of 161 

down-feed 163 

dry  return 162,  164 

elements  of  a 95 

layout  of  typical 160 

pressure  drop  in 116 

proportioning  of  return  mains  for 121 

proportioning  of  steam  mains  for 121 

removal  of  air  in 162 

return  mains  and  risers  in 162 

sizes  of  supply  and  return  pipes,  (table) .  .  128-129 

specification  for  typical 289 

supply  mains  and  risers  in 162 

taking  steam  from  street,  description  of 164 

up-feed 163 

various  types  of 162 

wet  return 163-164 

with  boiler  pressures  up  to  10-lb.,  description 

of 162 

with  boiler  pressures  up  to  50-lb.,  description 

of 163 

with  pump  and  receiver 164 

Modulation  valves,  lock-shield  type 170 

omission  of 103 

Type  W,  description  of 250 

dimensions  of 252 

ratings  of 237 

with  chain  attachment,  description  of 252 

with  chain  attachment,  installation  details  of  251 

with  extended  stem 252 

vacuum  systems 169 

Modulation  vent  traps 162 

description  and  dimensions  of 268-270 

typical  installation  details  of 268-269 

Modulation    vent    valves,    application     details 

of 268-271 

description  and  dimensions  of 270-271 

Monitors,  heat  losses  through 24 

Motor  valves,  attachments  for 294 

Muffler  oil  separator 257 

Multiple-unit  valves,  attachments  for 296 

National  Dry  Kiln  Co 187 

Noise  due  to  design  of  run-outs 134 

No.  7  Traps,  description  and  dimensions  of 216 

ratings  of 238 

Office  buildings,  considerations  leading  to  selec- 
tion of  type  of  heating  system  for 97 

Offset  connections,  (table) 319 

Oil  separator,  allowable  velocity  through 255 

method  of  draining  by  means  of  grease  trap .  .255 
receiver  and  muffler.  .  257 


Oil  separator,  Series  21,  description  of 254 

dimensions  of 256 

ratings  of 256 

Open  return-line  systems 95 

Operating  pressure 239 

Painting,  effect  of,  upon  radiation 49 

Pans,  vacuum  (see  Vacuum  pans) 
Paper-drying  machines,  application  of  Webster 

apparatus  to 191 

Partitions,  wood,  heat  transmission  factors  for. .   28 
Performance  of  stationary  steam  plants,  (table) .  334 

Piers,  steamship,  fire  protection  for 195 

Pipe,  air-carrying,  capacity  of  various  sizes  of, 

(table).. 69 

coils,  continuous  header  type  for  dry  kilns. . . .  182 

limit  of  length  of 43 

sectional  header  type  for  dry  kilns 184 

surface  in  square  feet  of,  (table) 56-57 

vertical  header  type  for  dry  kilns 185 

copper  and  brass  (see  Tubes) 

expansion  of,  (table) 318 

extra    and    double-extra    strong,    dimensions 

of,  (table) 317 

friction  of  water  in,  (table) 337 

standard  wrought  iron,  dimensions  of,  (table) .  316 

threads,  standard,  (table) 316 

Pipes,  grading  of  mains,  risers,  and  run-outs. ...   20 
sizes  of  supply  and  return  for  modulation  and 

vacuum  systems 128-129 

surface  factors  for 317 

Piping,  steam,  condensation  losses  in 113 

system,  down-feed 20 

Piston  speed  in  vacuum  pumps 140 

Plain  air  separating-tank,  description  of 264 

dimensions  of 266 

method  of  connecting  discharge  from  vacuum 

pump 144 

selection  of  size 138,  142 

Plans,  necessity  for 18 

Pockets,  lift  (see  Lift  fittings) 

Power-driven  reciprocating  vacuum  pumps 143 

Power  load 165 

Powers  of  numbers,  (table) 348-349 

Pressure,  and  weight,  comparisons  of,  (table) . .  .  333 

comparison  of  measures  of,  (table) 334 

corresponding  to  water-head,  (table) 333 

differences 12 

drop  in  modulation  systems 116 

in  steam  pipes 114 

in  vacuum  systems  through  return  trap.  120-121 

to  impart  initial  steam  velocity 110 

schedule  of 238 

drop  through  radiator  trap  in  modulation  sys- 
tems   117 

through  return  main 117 

through  vent  trap 117 

through  vent  valve 116 

in  pipes,  calculation  of  air 69 

loss  in  ducts,  (chart) 70 

operating 239 

-reducing  valve,  connections  for 216 

connections  to  water  accumulator 267 

vacuum  system 166 

regulator  (see  Pressure-reducing  valve) 

Priming  of  boilers 105 

Properties  of  air,  (table) 331 

Properties  of  saturated  steam,  (table) 328-329 

Public  buildings,  allowable  air  velocities  for  fan 

systems  in 67 

considerations  leading  to  selection  of  type  of 
heating  system  for 98 


358 


General  Index — Continued 


Public  buildings,  operating  pressure  in 239 

Pump    and    receiver,   conditions    requiring   use 

of 99 

connections  for  discharge  from  vacuum  pump 

to 119 

discharge  of  returns  from  vacuum  pump  to. . .  148 

use  of  in  a  modulation  system 164 

Pump  governor,  vacuum,  description  and  dimen- 
sions of 260 

Pump,  vacuum,  sizing,  (table) 138 

Radiation,  cast  iron  wall,  in  factory 12,   1 1 

direct,  definition  of 11 

example  of  computation  of 55,  58 

heat  emission,  (table) 45 

heat  emission  with  varying  room  tempera- 
tures, (chart) 47 

heat  emission  with  varying  steam  pressures.  46 
direct  and  indirect,  with  exhaust  systems.  ...   66 

effect  of  painting  on 49 

hot  water  pattern,  connections  of 43 

indirect,  definition  of 11 

formula  for  computing 51 

methods  of  computing 53-5 1 

methods  of  heating  by 53 

limit  of  length  of  waU . 43 

method  of  computing  and  selecting 42 

percentage  variation  in  heat  emission,  (chart) .   4 1 

relative  costs  of  cast  iron  direct,  (table) 51-52 

square  feet  of,  definition  of 12 

Radiators,  connections  on  vacuum  system 169 

direct^indirect,  data  for 55 

direct-indirect,  description  of 55 

enclosed,  decreased  efficiency  of,  (table) .  .  .  50-51 

enclosed  with  grilles 49 

enclosures 48 

indirect,  details  of  connection  to 52 

run-outs,  critical  velocity  in 132-13 1 

transmission  rate,  variation  of 11 

traps  (see  also  Return  traps) 

traps,  pressure  drop  through 117 

with  shield,  increased  efficiency  of,  (table) 51 

valves  (see  Modulation  valves) 
Railroad    switches,    method    of    prevention    of 

freezing 194 

Railroad  terminals 194-195 

Rating,  definition  of 233 

Ratings,  angle  valves,  (inlet) 237 

double-service  valves 237 

heavy-duty  traps 238-239 

modulation  valves 234-237 

modulation  vent  traps 240 

modulation  vent  valves 240 

No.  7  traps 237-238 

supply  and  return  mains 128-129 

supply  valves 237 

Sylphon  traps 237-238 

Type  W  modulation  valves 237 

Receiver  and  muffler  oil  separators 257 

Receiving    tanks,    description    and    dimensions 

of 264-266 

plain,    method   of   connecting   returns   from 

vacuum  pump  to 144 

selection  of  size  of 138.  1  12 

water-control,    method    of    connection    with 

vacuum  pump  and  feed-water  heater 145 

Reciprocating  vacuum  pumps,  power -driven. . . .  143 

proportions  of 138 

Recirculation  of  air  in  industrial  plants 67 

Reducing  valves  (see  Pressure-reducing  valves) 
Re-evaporation 261 


Re-evaporation,  chart. 157 

of  discharge  from  return  traps 156 

Registers,  area  of,  for  indirect  radiators 54 

Regulators,  damper  (see  Damper  regulators) 
pressure  (see  Pressure-reducing  valves) 
vacuum  (see  Vacuum  pump  governors) 

Relative  humidity 59 

Residences,  boiler  pressure  for 239 

considerations  leading  to  selection  of  type  of 

heating  system  for 97,  108 

example  of  heat  requirements  for,  computa- 
tion sheet 38-39 

heat  requirements  for,  plan  showing 36 

Resistance,  of  coils  and  air  washers 72 

of  fittings  to  steam  flow 113-115 

of  90°  elbows,  (table) 71 

of  pipes  to  air  flow,  calculation  of 69 

Return  mains,  definition  of 12 

for  modulation  systems,  proportions  of .  .  .  .121 

for  vacuum  systems,  proportions  of 122 

function  of 12 

ratings  of,  (table) 128-129 

sizing  of 141 

piping,  location  of 20 

modulation  systems 162-164 

tanks  (see  also  Tanks) 

uses  in  vacuum  system 171 

traps,  differential  type,  description  of 155 

float  type,  description  of 154 

method  of  running  return  pipe  to 187 

No.  7,  description  and  dimensions  of 246 

No.  7,  ratings  of 237-238 

objects  of  tests  in  laboratory 153 

outboard  type 156 

pressure  drop  allowable  through 117 

requirements  for  perfect  operation  of 241 

selection  of  size  and  type  of 238 

Sylphon,  description  of 242-245 

Sylphon,  dimensions  of 245 

Sylphon,  ratings  of 237-238 

testing 153 

tests  for  heating  efficiency  of 154 

thermostatic  type,  description  of 155 

use  of,  for  air  removal 186 

use  of,  in  lumber  dry  kilns 182,  181-186 

tubular  boilers,  dimensions  of,  (table) 330 

Returns,  dry,  methods  of  connections  for  modu- 
lation systems 228-229 

flashing  of 122 

intermittent 105 

methods  of  cooling 1 22 

Risers,  down-feed,  draining  through  radiator  220,253 

drainage  of 216-219,  224 

dripping,  vacuum  system 167 

method  of  providing  for  expansion  of 216 

modulation  systems,  methods  of  draining .  228-229 
return,  proportions  of,  for  vacuum  systems. .  .122 

up-feed  and  down-feed,  definition  of 12 

used  as  heating  surface 219 

Roof    construction,    heat    transmission    factors 

for 28 

Roof  glass,  heat  transmission  factors  for 29 

Roots  of  numbers,  (table) 318-349 

Rotating  vacuum  pumps 137 

Round  tanks,  contents  of,  (table) 335 

Run-outs,  above  floor 219 

critical  velocity  in 132-134 

in  floor 218 

sizing  of 135-136 

under  floor 219 

vacuum  systems 170 


359 


General  Index — Continued 


Salt,  manufacture  of 196 

Saturated  steam,  properties  of,  (table) 328-329 

School    rooms,    arrangement   of    diffusers   and 

direct  radiation  for 62 

Schools,  considerations  leading  to  selection  of 

type  of  heating  system  for 98,  108 

operating  pressures  for 239 

ventilating  system  for 61 

Selection  of  proper  type  of  steam  heating  system, 

fundamental  considerations  leading  to 97 

Separating  tanks  (see  Air-separating  tanks) 

Separators,  oil,  allowable  velocity  through 255 

method  of  draining 255 

receiver  and  muffler  type  of 257 

Series  21,  description  of 254 

dimensions  of 256 

ratings  of 256 

Separators,  steam,  Series  21,  description  and  di- 
mensions of 283-285 

Service  details  (see  separate  index) 

Sheet  metal  gauges,  (table) 351 

Shield,  radiator,  increase  in  efficiency  due  to 51 

Single-control     hydro-pneumatic     tanks,     con- 
nections to  geared-type  vacuum  pump 146 

description  and  dimensions  of 276-277 

Sizing  run-outs  for  various  grades  and  quan- 
tities  135-136 

Skin-friction 114 

Skylights,  heat  transmission  factors  for 29 

Slasher  equipment,  typical  application  of 189 

Slashers,  equipment  for 188 

Slope  of  pipe,  effect  of  upon  critical  velocity 133 

Specific  heat,  definition  of 9 

Specific  heats  of  materials,  (table) 342—343 

Specifications,  typical,  for  modulation  system. .  .289 

for  vacuum  system 286 

Spitzglass,  J.  M 112 

Square  feet  of  radiation,  definition  of 12 

Square  measure,  (table) 351 

Square  roots  of  numbers,  (table) 348-349 

Stacks  (see  Chimneys) 

indirect,  connections  for 225-227 

Standard  fittings,  dimensions  of,  (table) 320-323 

Standard  flanges,  dimensions  of,  (table) 320 

Standard  iron  pipe,  dimensions  of,  (table) 316 

Stand-pipes,  air-separating 144 

Stationary  steam  plants,  performance  of,  (table) .  334 

Steam,  (tables) 328-329 

-control  tanks,  control  of  boiler  feed  pump, 

connections 149 

-control  tanks,  description  of 265 

dimensions  of 266 

-driven  reciprocating  vacuum  pumps,  propor- 
tions of 138 

-driven  vacuum  pumps,   typical  connections 

to 150,166 

end,  vacuum  pump,  proportioning  of 143 

exhaust,  use  of,  in  dry  kilns 181 

flow,  effect  of  pipe  fittings  on 115 

flow  through  standard  pipes 112-115 

heating  systems,  types  of 95 

mains,  drainage  of 215 

mains,  dripping,  vacuum  systems 167 

plants,  stationary,  performance  of,  (table) 334 

requirements  for  tempering  air 61 

saturated,  properties  of,  (table) 328-329 

separators,  ratings  of 285 

separators,  Series  21,  description  and  dimen- 
sions of 283-285 

supply,  sources  of,  effect    upon    selection  of 

type  of  heating  system 103 

supply,  vacuum  systems,  source  of 165 


Steamship  piers,  fire  protection  for 195 

Sterilizers  (see  also  Hospital  equipment) 107 

Storage  of  returns 142 

Store  buildings,  considerations  leading  to  selec- 
tion of  type  of  heating  system  for 97 

Strainers,  dirt,  description  of 259 

dimensions  of 260 

suction,  and  vapor  economizer,  description  and 

dimensions  of 261-262 

description  of 258 

dimensions  of 259 

selection  of  size  of. 138,  141 

typical  connections  to 150 

use  of,  on  lumber  dry  kiln  coils 186 

Stratification,  factors  for 24 

formula  for  temperature  due  to 25 

illustration  of 23 

Street  steam,  supply 107 

system,  method  of  cooling  returns 222 

system,  vacuum 173 

Strength,  tensile,  of  materials,  (table) 343 

Suction  strainers 171 

and   vapor  economizer,   dimensions    and   de- 
scription of 261-262 

description  of 258 

dimensions  of 259 

selection  of  size  of 138,  141 

typical  connections  to 150 

Sugar,  manufacture  of 196 

Supply  mains,  and   risers  for  modulation  sys- 
tems   162 

definition  of 12 

for  modulation  systems,  proportions  of 121 

for  vacuum  systems,  proportions  of 122 

ratings  of,  (table) 128-129 

Supply  pipes,  location  of 20 

Supply  risers  (see  also  Risers) 

drainage  by  means  of  heavy-duty  traps 223 

Supply  valves  (see  also  Modulation  valves) 

ratings  of 237 

selection  of  size  and  type  of 239 

Surface  factors  for  pipes,  (table) 317 

Surfaces  and  volumes,  mensuration  of 352 

Switches,    railroad,    method    of    prevention    of 

freezing 194 

Sylphon  attachments  (see  Trap  attachments) . 

Sylphon  traps,  description  of 242-245 

dimensions  of 245 

ratings  of 237-238 

Tanks,  air-separating,  description  and  dimen- 
sions of 264-266 

air-separating,  selection  of  size  of 138,  141 

hvdro-pneumatic,  description  and  dimensions 

of 276-277 

selection  of  size  of 138,  142 

single  control,  connections  with  geared-type 

vacuum  pump 146 

plain  air-separating,  method  of  connecting  re- 
turns from 144 

plain,  selection  of  size  of 138,  142 

round,  contents  of,  (table) 335 

steam-control,  connections  to  boiler  feed  pump 

and  vacuum  pump 14 

selection  of  size  of 138,  142 

water-control,    method    of    connection    with 
vacuum  pump  and  to  feed-water  heater.  .145 

selection  of  size  of 138,  142 

Temperature,  at  ceiling,  air  mechanically  agitated  24 

at  ceiling,  high  rooms 2 

average  of  high  rooms 2 

comfortable 59 


360 


General  Index — Continued 


Temperature,  daily  maximum  and  minimum  in 

New  York 16-17 

difference,  factors  for,  (chart) 2 

due  to  stratification,  (formula?) 25 

for  various  rooms,  (table) 18 

increase  in  high  buildings 23 

requirements,  inside,  (table) 18 

Temperatures,  lowest  recorded,  (chart) 14 

Tensile  strength  of  materials,  (table) 343 

Terminals,  railroad. .194-195 

Tests  of  lumber  drying 180 

Tests  of  return  traps 153 

Theatre  ventilation 63 

Thermometer  scales,  conversion  of 353 

Thermostalic-type  return  trap,  description  of. .  .155 
Thermostatic  valve  No.  4,  trap  attachments  for. 294 

Threads,  pipe,  standards,  (table) 316 

Topography 15 

Transmission  of  heat  through  pipe 113 

Transmission  rate  of  radiators,  variation  of 11 

Trap  attachments 293 

for  motor  valves 294 

for  multiple-unit  valves 296 

for  thermo- valves 294 

for  various  types  of  valves 297 

for  water-seal  motors 294 

for  water-seal  traps 295 

Traps  (see  also  Return  traps) 

grease  and  oil,   description   and    dimensions 

of 257-258 

method  of  connecting  for  draining  oil  sepa- 
rator  255 

Traps,  heavy-duty,  high  differential 249 

heavy-duty,  Series  19T,  description  of 247 

dimensions  of 249 

ratings  of 239 

high-pressure     Sylpbon     (see     High-pressure 

Sylphon  traps) 
Hylo  (see  Hylo  traps) 

modulation  vent  (see  Modulation  vent  traps) 
proper  location  of  thermostatic  type  on  lumber 

dry  kiln  coils 186 

proper  type  for  lumber  dry  kilns 184 

return,  testing 153 

water-seal,  attachments  for 295 

Tubes,  boiler,  dimensions  of,  (table) 317 

brass  and  copper,  diameters  and  weights  of, 

(table) 315 

Tubular  boilers,  dimensions  of,  (table) 330 

United  States  Weather  Bureau,  daily  tempera- 
tures, 1916  to  1920 16-17 

lowest  temperatures  recorded,  (chart) 14 

Units,  heat,  definitions  of 9 

Up-feed  risers,  definition  of 12 

Up-feed  systems,  modulation 163 

vacuum 167-168 

V  acuum  governors,  sizing  of 138,  143 

typical  connections  of 151 

pans,  application  of  apparatus 201 

drainage  of 196 

pumps 137,  170 

belt-driven 143 

discharging  to  automatic  pump  and  receiver, 

connections  for 149 

electric-driven 137,  172 

geared-type 143 

governor 170 

governor,  description  and  dimensions  of. ...  260 

reciprocating,  proportions  of 138 

rotating 137 


Vacuum  governor,  sizing  of,  (table) 138 

steam-driven,  typical  connections  of..  .150,  166 

steam-ends,  proportioning  of 143 

water-and-air  ends,  proportioning  of 140 

regulators  (see  Vacuum  pump  governors) 

systems,  advantages  of 109 

classes  of  structures  for  application  of 96 

degree  of  vacuum  for 122 

descriptions  of 165 

different  types  of 165 

disposal  of  condensation  in 171 

down-feed 167-168 

dripping  mains  and  risers  for 167 

elements  of 96 

Hylo,  description  of 176 

pressure  drop  through  traps  in 121 

proportions  of  mains  and  risers  for 122 

pumps  for 170 

radiator  connections  for 169 

radiator  supply  valves  for 169 

requirements  of 12 

run-outs  for 170 

sizes  of  supply  and  return  mains,  (table)  127—129 

sources  of  steam  supply  for 165 

typical  layout  of 166 

typical  problem  of  sizing  pipe  for 123 

typical  specification  for 286 

up-feed 167-168 

using  street  steam 173 

ventilation  problems  with 172 

with  boiler  pressures  from  15  to  50-lb 172 

with  low  pressure  boilers 173 

with  power  boilers,  description  of 165 

Valves  (see  also  Modulation  valves) 
conserving  (see  Conserving  valves) 
effect  of,  upon  flow  of  steam  through  pipes. .  .115 
modulation  vent  (see  Modulation  vent  valves) 

radiator  outlet,  attachments  for 297 

Vapor  economizer  and  suction  strainer,  descrip-   • 

tion  and  dimensions  of 261 

Velocity,  air  for  fan  systems  in  public  buildings.   67 
air  for  fan  systems  in  various  types  of  buildings  68 

allowable  through  oil  separators 256 

critical,  in  radiator  run-outs 132-134 

-head  factors,  (table) 348-349 

initial,  of  steam  flow,  (table) 110 

Vent  traps,  high-duty,  application  of 120 

location  of 120 

modulation  (see  Modulation  vent  traps) 

pressure  drop  through 117 

valves,   modulation    (see  Modulation   vent 
valves) 

pressure  drop  through 117 

Ventilation,  apparatus,  selection  of 72 

banquet  halls  and  meeting  rooms 64 

churches 63 

direct-indirect  system 60 

exhaust,  for  industrial  plants 65 

gravity  indirect  system 60 

kitchens 64 

methods 60 

problems 59 

problems  in  design  of  vacuum  system 172 

schools 61-62 

theatres  and  auditoriums 63 

Vento  radiation,  connections  for  draining.  .225-227 
Volumes  and  surfaces,  mensuration  of 352 

\Af  Type  modulation  valves,  description  of 250 

dimensions  of 252 

ratings  of 237 

\\  nil  radiation,  cast  iron,  in  factory 42,  44 


361 


General  Index — Continued 


Wall  radiation,  methods  of  applying 102,  104 

illustration  of  application  in  factory 44 

limit  of  length  of. 43 

Walls,  heat  transmission  factors  for,  brick 26 

clapboard 25 

concrete  faced  with  brick  or  stone 26—27 

corrugated  iron 26 

hard  stone  or  concrete 27 

hollow  tile 27 

hollow  tile  faced  with  brick 26 

interior 25 

sandstone  or  limestone 27 

stucco  on  studs 26 

Warming-up  period 10 

Warp  drying 190 

Water  accumulator,  description  and  dimensions 

of 267 

typical  connections  to  conserving  valve 173 

typical    connections    to    pressure-reducing 

valve 267 

-and-air  end,  vacuum  pump,  proportioning  of.  140 

benefits  of  returning  to  boiler 13 

-control  tank,  description  of 264 

dimensions  of 266 

method  of  connection  to  vacuum  pump  and 
feed-water  heater 145 


Water-control  tank,  selection  of  size  of .  ...  138,  142 

conversion  factors  of,  (table) 338 

cost  at  stated  rates,  (table) 338 

-seal  motors,  attachments  for 294 

-seal  traps,  attachments  for 295 

weight  and  volume  at  various  temperatures, 
(table) 332 

Weather  Bureau,  United  States,  lowest  tempera- 
tures recorded,  (chart) 14 

Webster  apparatus  (see  separate  index) 

systems  of  steam  heating,  descriptions  of 161 

Weight,  and  pressure,  comparison  of,  (table) .  .  .  333 

measures  of,  (table) 351 

of  1  gallon  of  water  at  various  temperatures, 
(table) 335 

Wet-returns,  modulation  systems 162,  164 

Windows,  double-hung,  air  infiltration  through, 

(chart) 32 

heat  transmission  factors  for 28 

heat  transmission  factors  for,  above  datum. ...   28 

Wire  gauges,  comparison  of,  (table) 350 

Wood  partitions,  heat  transmission  factors  for . .  28 

Yarns,  sizing  and  drying  of 188 

Y.M.C.A.   buildings,   considerations  leading  to 
selection  of  type  of  heating  system  for 106 


Tables 


Air,  heat  required  to  raise  temperature  of..  .  .72-73 

infiltration,  B.t.u.  required  for 33 

pressure  loss  in  ducts,  chart  of 70 

properties  of 331 

quantities  required  for  ventilation 67 

resistance  of  elbows 71 

velocities  for  fan  systems  in  public  buildings. .   67 
velocities  for  fan  systems  in  various  types  of 

buildings 68 

Altitude,  effect  of,  upon  boiling  point  of  water. .  332 

Anthracite  coal,  heat  values  of 340-341 

Area,  measures  of 351 

Areas  of  circles 346-347 

Avoirdupois  weight 351 

Bends,  effect  upon  steam  flow  through  pipes.  .  .115 

Bituminous  coal,  heat  values  of 339-340 

Boiler  tubes,  dimensions  of 317 

Boilers,  return  tubular,  dimensions  of 330 

Boiling  point  of  water  at  various  altitudes 332 

Brass  tubes,  diameters  and  lengths  of 315 

Calorific  values  of  coal 340 

Ceilings,  heat  transmission  factors  for 30 

Centigrade,  conversion  to  fahrenheit  scale 353 

Chimney  lining,  dimensions  of  standard  sizes.  .  .   75 

Circles,  circumferences  and  areas  of 346-347 

Coal,  anthracite,  heat  values  of 340-311 

bituminous,  heat  values  of 339—340 

calorific  value  of 340 

classification  of 339-340 

grate  areas  required  for  burning 92 

rates  of  combustion  of 92 

Coils,  pipe,  surface  in  square  feet 56-57 

Combustion  rates  for  various  coals 92 

Connections,  offset 319 

Contents,  measures  of 351 

of  round  tanks 335 

Copper  tubes,  diameters  and  lengths  of 315 

Cost  of  direct  cast  iron  radiation,  relative 52 

Cube  roots  of  numbers 3 18-3 19 


Cubic  measure  .....................  .  ........  351 


l  equivalents  of  fractions  ..........  348-349 

of  inches  .............................  344—345 

Densities  of  materials  .......................  342 

Differential  pressures  through  traps  and  valves.  238 
Direct  radiation,  heat  emission  ...............  45 

heat  emission  with  varying  steam  pressures  ....  46 

relative  costs  of  cast  iron  ...................   52 

Direct-indirect  radiators,  data  for  .............   55 

Doors,  heat  transmission  factors  for  ...........   28 

Ducts,  air-carrying,  capacity  of  various  sizes  of  .   69 
air  pressure  loss  in,  chart  of  ................   70 

resistance  of  air  in  elbows  of  ................  71 

Economy  of  feed-water  heaters  ..............  301 

Efficiency,  increase  in  radiation  with  shield  .....  51 

decrease  of,  in  enclosed  radiators  ............   50 

Elbows,  friction  of  water  in  ..................  336 

resistance  of  air  line  .......................  71 

Electrical  units,  definitions  of  .................  352 

Engine,  horse  power  of  ......................  329 

Expansion,  wrought  iron  pipe  ................  318 

solids,  lineal  ..............................  344 

Extra-heavy  fittings,  dimensions  of  ........  324-327 

flanges,  dimensions  of  ......................  324 

iron  pipe,  dimensions  of  ....................  317 

Factors,  basic,  for  heat  transmission  ..........  25 

Feed-water  heaters,  economy  chart  for  .........  301 

Fittings,  effect  of,  upon  steam  flow  ............  115 

extra-heavy  flanged,  dimensions  of  ......  324-327 

extra-heavy  flanged,  rules  for  .........  .  .....  324 

screwed  cast  iron,  dimensions  of  ............  319 

standard  flanged,  dimensions  of  .........  320-323 

standard  flanged,  rules  for  .................  320 

Flanges,  extra-heavy,  dimensions  of  ...........  324 

standard,  dimensions  of  ....................  320 

Floors,    above    cold    space,    heat    transmission 
factors  for  ................................   29 

laid  on  ground,  heat  transmission  factors  for.   30 


362 


Index  of  Tables — Continued 


Flow  of  water,  through  elbows  ...............  .336 

through  pipes  .............................  337 

Fractional  equivalents  of  decimals  .........  348-349 

Friction,  air  in  ducts,  chart  of  ................  70 

loss,  comparison  between  round  and  rectan- 
gular ducts  .............................  71 

water  in  elbows  ...........................  336 

water  in  pipes  ............................  337 


of  water,  weight  at   various   tempera- 
tures ..................................  335 

Gauges,  sheet  metal  .........................  351 

wire,  comparison  of  .......................  350 

Glass,  roof,  neat  transmission  factors  for  .......  29 

Grate  surfaces  for  various  grades  of  coal  .......  92 

H«'ails  of  water  corresponding  to  pressures  .....  333 

Heat,  emission  of  direct  radiation  with  varying 
room  temperatures  ......................  47 

emission    of    direct    radiation    with    varying 
steam  pressures  .........................  46 

emission  of  radiation,  percentage  variation  ....  44 

required  to  raise  temperature  of  air  ........  72-73 

transmission,  basic  factors  for  ..............  25 

transmitted  through  steam  pipes  ........  114,  116 

values  of  various  kinds  of  coal  ..........  339-340 

Horsepower,  of  an  engine  .....................  329 

of  return  tubular  boilers  ...................  330 

Hydro-pneumatic  tanks,  selection  of  size  .  .  .138,  142 

I  nfiltration,  B.t.u.  required  for  ...............   33 

chart  for  double-hung  windows  .............  32 

Inside  temperature  requirements  ..............   18 

Iron  pipe,  dimensions  of  .................  316-317 

Liquid  measure  ............................  351 

Long  measure  ..............................  351 

Loss,  friction,  in  round  and  rectangular  ducts.  .  .  71 

Mains,  ratings  for  return  ................  128-129 

ratings  for  supply  .....................  128-129 

Materials,  densities  of  .......................  342 

specific  heats  of  .......................  342-343 

tensile  strength  of  .........................  343 

weights  of  ................................  341 

Measures  of  pressure,  comparison  of  ...........  334 

Mensuration  of  surfaces  and  volumes  ..........  352 

Offset  connections  ..........................  319 

Partitions,  wood,  heat  transmission  factors  for.    28 
Performance  of  stationary  steam  plants  ........  33  1 

Pipe,  air-carrying,  capacity  of  various  sizes  of.  .  .   69 
coils,  surface  in  square  feet  ...............  56-57 

copper  and  brass  (see  Tubes) 

expansion  of  ..............................  318 

e\lrn  and  double-extra  strong,  dimensions.  .  .  .317 

friction  of  water  in  ........................  337 

si/os  of  supply  and  return  ..............  128-129 

standard  wrought  iron,  dimensions  of  ........  316 

surface  factors  for  .........................  317 

threads,  standard  .........................  316 

Plain  air-separating  tanks,  selection  of  size.  138,  142 
Powers  of  numbers  ......................  318-349 

Pressure.  mid  weight,  comparison  of  ...........  333 

comparison  of  measures  of  .................  331 

corres|x>niliiiK  to  water  heads  ...............  333 

drop  to  impart  initial  steam  velocity  ........  110 

drops,  schedule  of  .........................  238 

loss  in  ducts,  chart  of  ......................   70 

Properties  of  air  ............................  331 


Properties  of  saturated  steam 328-329 

Public  buildings,  allowable  air  velocities  in  fan 

systems 67 

Pumps,  vacuum,  sizing  of 138 

Radiation,  direct,  heat  emission 45 

direct,  heat  emission  with  varying  room  tem- 
peratures    47 

direct,    heat    emission    with    varying    steam 

pressures 46 

percentage  variation  in  heat  emission 44 

relative  costs  of  cast  iron  direct 52 

Radiators,  direct-indirect,  data  for 55 

enclosed,  decreased  efficiency  of 50 

with  shield,  increased  efficiency  of 51 

Ratings  of  supply  and  return  mains 128-129 

Receiving  tanks,  selection  of  size  of 138,  142 

Re-evaporation  chart 157 

Resistance,  of  90°  elbows 71 

to  steam  flow  of  fittings 115 

Return  mains,  modulation  systems,  proportions 

of 121 

ratings  of 128-129 

Return  tubular  boilers,  dimensions  of 330 

Roof  glass,  heat  transmission  factors  for 29 

Roots  of  numbers 348-349 

Round  tanks,  contents  of 335 

Run-outs,  sizing  of 135-136 

Saturated  steam,  properties  of 328-329 

Sheet  metal  gauges 351 

Shields,  radiator,  increase  in  efficiency  due  to. . .  51 
Sizing  run-outs  for  various  grades  and  quan- 
tities  135-136 

Skylights,  heat  transmission  factors  for 29 

Specific  heats  of  materials 342-343 

Square  measure 351 

Square  roots  of  numbers 348-349 

Standard  fittings,  dimensions  of 320-323 

Standard  iron  pipe,  dimensions  of 316 

Stationary  steam  plants,  economic  performance 

of 334 

Steam-driven  reciprocating  vacuum  pump,  pro- 
portions of 138 

Steam,  flow,  effect  of  pipe  fittings  on 115 

flow  through  standard  pipes 114-115 

plants,  economic  performance  of 334 

properties  of 328-329 

saturated,  properties  of 328-329 

Strainer,  suction,  selection  of  size  of 138,  141 

Strength,  tensile,  of  materials 343 

Suction  strainer,  selection  of  size  of 138,  141 

Supply  mains,  for  modulation  systems,  propor- 
tions of 121 

ratings  of 128-129 

Surface  factors  for  pipe 317 

Surfaces  and  volumes,  mensuration  of 352 

Tanks,  air-separating,  selection  of  size  of.  .138,  141 

hydro-pneumatic,  selection  of  size  of 138,  142 

plain,  selection  of  size  of 138,  142 

round,  contents  of 335 

steam-control,  selection  of  size  of 138,  142 

water-control,  selection  of  size  of 138,  142 

Temperature  difference,  chart  of  factors  for.  ...   22 

Temperature  for  various  rooms 18 

Temperature  requirements,  inside 18 

Tensile  strength  of  materials 343 

Thermometer  scales,  conversion  of 353 

Threads,  pipe,  standard 316 

Transmission  of  heat  through  pipe lit,  116 

Tubes,  boiler,  dimensions  of 317 


363 


Index  of  Tables — Continued 


Tubes,  copper,  brass,  diameters  and  weights  of.. 315 
Tubular  boilers,  dimensions  of 330 

Vacuum  governors,  sizing  of 138, 143 

Vacuum  pumps,  reciprocating,  proportions  of. .  .138 

sizing  of 138 

Valves,  effect  of,  upon  flow  of  steam  through  pipes  115 
Velocities  of  air  for  fan  systems  in  public  build- 
ings   67 

Velocity-head  factors 348-349 

Volumes  and  surfaces,  mensuration  of 352 

Walls,  heat  transmission  factors  for,  brick 26 

clapboard 25 

concrete  faced  with  brick 26 

concrete  faced  with  stone 72 


Walls,  corrugated  iron 26 

hard  stone  or  concrete 27 

hollow  tile 27 

hollow  tile  faced  with  brick 26 

interior 25 

sandstone  or  limestone 27 

stucco  on  studs 26 

Water,  conversion  factors 338 

cost  at  stated  rates 338 

weight  and  volume  at  various  temperatures.  .332 
Water-control  tanks,  selection  of  size  of..  .  .138,  142 

Weight,  and  pressure,  comparison  of 333 

measures  of 351 

of  one  gallon  of  water  at  various  temperatures.  335 

Windows,  heat  transmission  factors  for 28 

Wire  gauges,  comparison  of 350 

Wood,  partitions,  heat  transmission  factors  for. .  28 


Webster  Service  Details 


Accumulator,  water  (see  Water  accumulator) 
Air-separating  tank,  plain,  method  of  connecting 

returns  from  vacuum  pump 144 

water-control,  method  of  connecting  to  vac- 
uum pump  and  to  feed-water  heater 145 

Automatic  pump  and  receiver,  connections  for 
discharge  from  vacuum  pump 149 

Bain  marie  (see  Kitchen  equipment) 
Ball  check  valves  (see  Modulation  vent  valves) 
Basement  radiation,  method  of  draining,  modu- 
lation system 229,  232 

Blanket  warmers  (see  Hospital  equipment) 

Blast  heaters,  connections  for 225-227 

Blower  sections,  connections  for 225-227 

Boiler-feed  pump,  and  receiver,  connections  for 

discharge  from  vacuum  pump 149 

controlled  by  air-separating  tank,  connections 

for 149 

Boiler  feeder  connections  with  double-control 
hydro-pneumatic  tank  and  geared-type  vac- 
uum pump _ 147 

Boilers,  modulation  system,  connections  for  ther- 
mostatic  and  for  time  clock  control  of 

damper  regulator ; 231 

modulation  system,  method  of  connection  for 
parallel  operation 230 

Cloth-drying  machines,  application  of  Webster 
apparatus  to 190 

Coffee  Urns  (see  Kitchen  equipment) 

Coils,  design  of,  for  lumber  kilns 183 

drainage  of 220-221 

Combination  gauges,  connections  for 268 

Condensed  milk  (see  Condensories) 

Condensories,  application  of  Webster  system 
to 196 

Conserving  system,  typical  layout  of 173 

Controllers,  Hylo  (see  Hylo  controllers) 

Cooking,  steam  appliances  for  (see  Kitchen 
equipment) 

Damper  regulators,  methods  of  control  by 
thermostat  and  by  time  clock 231 

Double-control  hydro-pneumatic  tank,  used  in 
connection  with  geared-type  vacuum  pump 
and  boiler  feeder _ 147 

Double-service  valves,  typical  installation,  de- 
tail  253 

Down-feed  risers,  draining  through  radiator .  220,  253 


Dry  kilns,  design  of  pipe  coils  for 18-* 

plans  showing  use  of  continuous  header  coil 

for 182 

plans  showing  use  of  sectional  header  coil  for. .  184 
plans  showing  use  of  vertical  header  coil  for .  .  185 
Dry  returns,  methods  of  connections  for  modu- 
lation systems 228-229 

Expansion  loops  in  risers 216 

Feeder,  boiler  (see  Boiler  feeder) 

Feed-water  heater,  gravity  return  to 222 

typical  connections,  steam-control  type 304 

typical  connections,  water-control  type 303 

Fire  protection  for  exposed  water  hydrants 195 

Fittings,  lift  (see  Lift  fittings) 

Gauges  (see  Combination  gauges) 

combination  (see  Combination  gauges) 

typical  connections  for : ._.  .150 

Geared-type  vacuum  pump,  connections  with 
boiler  feeder  and  double-control  hydro- 
pneumatic  tank 147 

connections  with   single-control  hydro-pneu- 
matic tank 146 

Generator,  hot  water  (see  Hot  water  generator) 
Governor,  vacuum  pump   (see  Vacuum  pump 
governor) 

vacuum  pump,  typical  connections  of 151 

Grease  trap,  method  of  connecting  for  draining 
of  oil  separator 255 

Heater,  blast  (see  Blast  heater) 
feed-water  (see  also  Feed-water  heater) 
feed-water,  connections  from  water-controlled 

air-separating  tank 145 

Heavy-duty  trap,  connections  for  coils  drained 

through  one  trap  in  lumber  kilns 187 

sectional  drawing  of _.......  .225 

High-differential  heavy-duty  trap,  application  to 

drainage  of  vacuum  pans 201 

High-pressure  Sylphon  trap,  application  for  hos- 
pital equipment 202 

application  for  kitchen  equipment 203 

application  to  hydrants  to  prevent  freezing. .  .195 

typical  installation  for  railroad  switches 191 

Hospital    equipment,    application    of    Webster 

system  to 202 

Hot  water  generator,  connections  for. .  222,  227,  229 


364 


Index  of  Webster  Service  Details — Continued 


Hydro-pneumatic    tank,    double-control,    con- 
nections with   geared-type   vacuum   pump 

and  boiler  feeder. 147 

single-control,   connections   with  geared-type 
vacuum  pump 146 

Hylo   systems,    typical   connections   of   special 
apparatus 177 

Indirect  radiation,  connection  for  air  supply. . .   65 

Indirect  radiator,  details  of  connection  to 52 

Indirect  stack,  connections  for 225-227 

Joint,  expansion  (see  Expansion  joint) 

Kettle,  cooking  (see  Kitchen  equipment) 

Kilns,  design  of  pipe  coils  for 183 

plans  showing  use  of  continuous  header  coils . .  182 
plans  showing  use  of  sectional  header  coil. .  .  .184 
plans  showing  use  of  vertical  header  coil  for. .  185 

Kitchen  equipment,  application  of  Webster  sys- 
tem to 203 

Kitchen,  ventilating  equipment  for 64 

Lift  fittings,  application  for  "step-up"  lifts. .  .139 
Lift  pockets  (see  Lift  fittings) 

Lifts,  method  of  design  for  "step-up" 139 

Lubricators,  sight,  typical  connections  of 151 

Mains,  method  of  dripping 215 

steam  (see  Risers) 
Milk  condensories  (see  Condensories) 

Modulation  system,  typical  layout 160 

system,  valves  with  chain  attachment,  in- 
stallation details 251 

vent  traps,  typical  installation  details 268-269 

vent  valves,  application  details 268-271 

Oil  separators,  method  of  draining  by  means  of 
grease  trap 255 

Pans,  vacuum  (see  Vacuum  pans) 

Paper-drying  machine,  application  of  Webster 
apparatus  to 191 

Pier,  steamship,  fire  protection  for 195 

Pipe  coils,  drainage  of 220-221 

use  of  continuous  header  type  in  dry  kilns.. .  .  182 

use  of  sectional  header  type  in  dry  kilns 184 

use  of  vertical  header  type  in  dry  kilns 185 

Plain  air-separating  tanks,  method  of  connecting 
discharge  from  vacuum  pump 144 

Pockets,  lift  (see  Lift  fittings) 

Pressure-reducing  valve,  connections  for 216 

connections  to  water  accumulator 267 

Pressure  regulators  (tee  Pressure-reducing  valve) 

Pump  and  receiver,  connections  for  discharge 
from  vacuum  pump 149 

Radiator  traps  (see  Return  traps) 

valves  (see  Modulation  valves) 
Radiators,  indirect,  details  of  connection  to ....   52 
Railroad  switch,  method  of  prevention  of  freez- 
ing  194 

Receiving  tanks,  plain,  method  of  connecting  re- 
turns from  vacuum  pump 144 

water-control,     method     of     connection     to 

vacuum  pump  and  feed-water  heater 145 

Reducing  valves  (see  Pressure-reducing  valves) 
Regulators,  damper  (see  Damper  regulators) 
pressure  (see  Pressure-reducing  valves) 
vacuum  (see  Vacuum  pump  governors) 
Returns,  dry,  methods  of  connections  for  modu- 
lation system 228-229 


Returns  tank  (see  Tanks) 

Risers,  down-feed,  draining  through  radiator  220,  253 

drainage  of 216-219,  224 

method  of  providing  for  expansion  of 216 

modulation  system,  methods  of  draining .  228-229 
used  as  heating  surface 219 

Run-outs,  above  floor 219 

in  floor 218 

under  floor 219 

Separating  tanks  (see  Air-separating  tank) 

Separators,  oil,  method  of  draining 255 

Single-control  hydro-pneumatic  tanks,  connec- 
tions to  geared-type  vacuum  pump 146 

Slasher  equipment,  typical  installation  of 189 

Stack,  indirect,  connections  for 225-227 

Steam-control    tanks,    control    of    boiler    feed 

pump,  connections 149 

Steam-driven  vacuum  pumps,   typical  connec- 
tions of 150,  166 

Steam  mains,  drainage  of 215 

Steamship  piers,  fire  protection  for 195 

Sterilizers  (see  Hospital  equipment) 

Suction  strainers,  typical  connections  of 150 

Street  system,  method  of  cooling  returns  from . .  222 
Supply  risers  (see  also  Risers) 

drainage  by  means  of  heavy-duty  trap 223 

Supply  valves  (see  Modulation  valves) 
Switches,    railroad,    method    of   prevention   of 
freezing 194 

Tanks,  hydro-pneumatic  single-control,  connec- 
tions with  geared-type  vacuum  pump 146 

plain  air-separating,  method  of  connecting  re- 
turns from 144 

steam-control,    connections    showing    boiler- 
feed  pump  and  vacuum  pump 149 

water-control,  method  of  connection  with  vac- 
uum pump  and  to  feed-water  heater 145 

Traps  (see  also  Return  traps) 

grease  and  oil,  method  of  connecting  for  drain- 
ing oil  separator 255 

high-pressure  Sylphon  (see  High-pressure  Syl- 
phon  traps) 

Hylo  (see  Hylo  traps) 

modulation  vent  (see  Modulation  vent  traps) 

proper  location  of  thermostatic,  on  lumber  dry 
kiln  coils 186 

Vacuum  governors,  typical  connections  of 151 

pans,  application  of  apparatus 201 

pumps,  discharging  to  automatic  pump  and 

receiver,  connections  of 149 

pumps,     steam-driven,     typical    connections 

of 150,166 

regulators  (see  Vacuum  pump  governors) 

system,  typical  layout  of 166 

Valves  (see  also  Modulation  valves) 
conserving  (see  Conserving  valves) 
modulation  vent  (see  Modulation  vent  valves) 
Vent  traps,  modulation  (see  Modulation  vent 

traps) 

valves,    modulation    (see    Modulation    vent 
valves) 

Ventilating  equipment  for  kitchens 64 

Vento  radiation,  connections  for  draining..  .225-227 

\A/ater  accumulators,  typical  connections  to  con- 
serving valve 173 

typical  connections  to  pressure-reducing  valve.  267 

Water-control  tanks,  method  of  connection  to 
vacuum  pump  and  to  feed-water  heater 145 


365 


Webster  Apparatus 


Accumulator,  water  (see  Water  accumulator) 
Air-separating  tanks,  description  and  dimensions 

of. .. 264-266 

Anchor  points,  allowable  distance  between 283 

Attachments  for  Sylphon  traps  (see  Trap  attach- 
ments) 

Ball  check  valves  (see  Modulation  vent  valves) 
Boiler  feeder,  description  and  dimensions  of ....  274 

Check  valves,  special,  for  modulation  systems, 

application  details  of 268-269 

Combination  gauges 267 

connections  for 268 

Conserving  valves,  description  and  dimensions 

of 273 

illustration  of 174 

Controllers,  Hylo  (see  Hylo  controllers) 

Damper  regulators,  description  and  dimensions 
of 271 

Dirt  strainers,  description  of 259 

dimensions  of 260 

Double-control  hydro-pneumatic  tanks,  descrip- 
tion and  dimensions  of 276-277 

Double-service  valves,  description  of 252-254 

dimensions  of 254 

ratings  of 237 

typical  installation  detail  of 253 

Drag  lifts 263 

Economizer,  vapor,  and  suction  strainer,  des- 
cription and  dimensions  of 261-262 

Economy  table,  feed-water  heaters 301 

Evaporation,  boiler,  measurement  of 313 

Expansion  joints,  allowable  distances  between 

anchor  points  of 283 

description  and  dimensions  of 278-282 

Feeder,  boiler  (see  Boiler  feeder) 

Feed-water  heaters,  description  of 302-313 

dimensions,  Webster  Class  EB 310 

dimensions,  Webster  Class  EBP 311 

dimensions,  Webster  Class  EF 313 

dimensions,  Webster  Class  EFP 312 

economy  chart  of 301 

typical  connections,  steam-control  type 304 

typical  connections,  water-control  type 303 

Fittings,  lift  (see  Lift  fittings) 

Fuel  saving  by  preheating  feed  water 301 

Gauges  (see  also  Combination  gauges) 
combination  (see  Combination  gauges) 
typical  connections  for 150 

Governors,  vacuum  pump  (see  also  Vacuum  pump 

governors) 
typical  connections  for 151 

Grease  traps,  description  of 257 

dimensions  of _.  ;.  .  .  . 258 

method  of  connection  for  draining  oil  sepa- 
rator   255 

Heater-meter,  Webster-Lea,  description  of. 313-314 
Heaters,  feed-water  (see  Feed-water  heaters) 
Heavy-duty  traps,  connection  for  coils  drained 

through  one  trap  in  lumber  dry  kilns 187 

high-differential  type,  description  and  dimen- 
sions of 249 

method  of  running  return  pipe  in  lumber  dry 
kilns 187 


Heavy-duty  traps,  Series  19T,  description  of  .  .  .247 

Series  19T,  dimensions  of 249 

Series  19T,  ratings  of 239 

use  in  lumber-drying  kilns 182,  186 

High-differential  heavy-duty  traps,  description 

and  dimensions  of 249 

High-pressure   Sylphon    traps,   description   and 

dimensions  of 275 

Hydro-pneumatic  tanks,  description  and  dimen- 
sions of 276-277 

selection  of  size  of 138,  142 

Hylo  controllers,  dimensions  of 272 

Hylo  traps,  dimensions  of 272 

Joints,  expansion  (see  Expansion  joints) 

Lift  fittings,  Series  20,  description  of 263 

Series  20,  dimensions  of 264 

typical  applications  of 263 

Lift  pockets  (see  Lift  fittings) 

Lifts,  drag 263 

IVleter-heaters  (see  Heater-meters) 

Modulation  system,  typical  specification  for. .  .  .289 

valves,  Type  W,  description  of . 250 

Type  W,  dimensions  of 252 

Type  W,  ratings  of 237 

Type  W,  with  chain  attachment,  description 

of 252 

Type  W,  with  extended  stem 252 

with  chain  attachment,  installation  details 

of 251 

vent  traps,  description  and  dimensions  of  .268-270 

typical  installation  details  of 268-269 

vent  valves,  application  details  of 268-271 

description  and  dimensions  of 270-271 

Motor  valves,  attachments  for 294 

Muffler  oil  separators 257 

Multiple-unit  valves,  attachments  for 296 

No.  7  traps,  description  of 246 

dimensions  of 246 

ratings  of 238 

Oil  separators,  allowable  velocity  through 255 

method    of    draining    by    means    of    grease 

trap 255 

receiver  and  muffler 257 

Series  21,  description  of 254 

Series  21,  dimensions  of 256 

Series  21,  ratings  of 256 

Plain  air-separating  tanks,  description  of 264 

dimensions  of 266 

selection  of  size 138,  142 

Pockets,  lift  (see  Lift  fittings) 

Pressure-reducing  valves,  connections  to  water 
accumulator 267 

Pressure  regulators  (see  Pressure-reducing  valves) 

Pump  governors,  vacuum,  description  and  di- 
mensions of 260 

Pumps,  vacuum,  table  of  sizing 138 

Radiator  traps  (see  Return  traps) 
Radiator  valves  (see  Modulation  valves) 

Receiver  and  muffler  oil  separator 257 

Receiving   tanks,    description    and    dimensions 

of 264-266 

selection  of  size  of 138,  142 

Reducing  valves,  (see  Pressure-reducing  valves) 


36ti 


Index  of  Webster  Apparatus — Continued 


Regulators,  dumper  (see  Damper  regulators) 
pressure  (see  Pressure-reducing  valves) 
vacuum  (see  Vacuum  pump  governors) 

Return  traps,  method  of  running  return  pipe  to.  187 

No.  7,  description  and  dimensions  of 246 

No.  7,  ratings  of 237-238 

requirements  for  perfect  operation  of 241 

Sylphon,  description  of 242-245 

Sylphon,  ratings  of .237-238 

use  for  air  removal  in  lumber  dry  kilns 186 

use  in  lumber  dry  kilns 182,  184-186 

Return  tanks  (see  Tanks) 

Separating  tanks  (see  Air-separating  tanks) 

Separators,  oil,  allowable  velocity  through 255 

method  of  draining 255 

receiver  and  mufller  type 257 

Serifs  21,  description  of 254 

Series  21,  dimensions  of 256 

Series  21,  ratings  of 256 

Separators,   steam,   Series   21,   description   and 
dimensions  of 283-285 

Single-control  hydro-pneumatic  tanks,  descrip- 
tion and  dimensions  of 276-277 

Specifications,  typical,  modulation  system 289 

typical,  vacuum  system 286 

Steam-control  tanks,  description  of 265 

dimensions  of 266 

Steam  separators,  ratings  of 285 

Series  21,  description  and  dimensions  of.  .283-285 

Strainers,  dirt,  description  of 259 

dirt,  dimensions  of 260 

suction,  and  vapor  economizer,  description  and 

dimensions  of 261-262 

description  of 258 

dimensions  of 259 

selection  of  size  of 138,  141 

use  of,  on  lumber  dry  kiln  coils 186 

Suction  strainer,  and  vapor  economizer,  descrip- 
tion and  dimensions  of 261-262 

description  of 258 

dimensions  of 259 

selection  of  size  of 138,  141 

typical  connections  for 150 

Supply  valves  (see  Modulation  valves) 

Sylphon  attachments  (see  Trap  attachments) 

Sylphon  traps,  description  of 242-245 

dimensions  of 245 

ratings  of 237-238 

Tanks,  air-separating,  description  and  dimen- 
sions of 264-266 

air-separating,  selection  of  size  of 138,  141 

Tanks,  hydro-pneumatic,  description  and  dimen- 
sions of 276-277 

hydro-pneumatic,  selection  of  size  of.  ...  138,  142 
plain,  selection  of  size  of 138,  142 


Tanks,  steam-control,  selection  of  size  of.  .  .138,  142 

water-control,  selection  of  size  of 138,  142 

Thermostatic  valve  No.  4,  trap  attachments  for. 294 

Trap  attachments 293 

for  motor  valves 294 

for  multiple-unit  valves 296 

for  thermo  valves 294 

for  various  types  of  valves 297 

for  water-seal-motors 294 

for  water-seal  traps 295 

Traps  (see  also  Return  traps) 

grease  and  oil,  description  of 257 

dimensions  of 258 

method  of  connecting  for  draining  oil  sepa- 
rator  255 

heavy-duty  series  19T,  description  of 247 

dimensions  of 249 

ratings  of 239 

high-pressure  Sylphon  (see  High-pressure  Syl- 
phon traps) 
Hylo  (see  Hylo  traps) 

modulation  vent  (see  Modulation  vent  traps) 
proper  location  of  thermostatic  type,  on  lumber 

dry  kiln  coils 186 

proper  type  for  lumber  dry  kilns 184 

water-seal,  attachments  for 295 

Vacuum  governors,  typical  connections  for.  ...  151 
pump  governors,  description  and  dimensions 

of 260 

regulators  (see  Vacuum  pump  governors) 

system,  typical  specification  for 286 

Valves  (see  also  Modulation  valves) 
conserving  (see  Conserving  valves) 
modulation  vent  (see  Modulation  vent  valves) 

radiator  outlet,  attachments  for 297 

Vapor  economizer  and  suction  strainer,  descrip- 
tion and  dimensions  of 261 

Velocity,  allowable,  through  oil  separators 256 

Vent  traps,  modulation   (see  Modulation  vent 

traps) 

Vent  valves,  modulation  (see  Modulation  vent 
valves) 

W  Type  modulation  valves,  description  of . . .  .250 

dimensions  of 252 

ratings  of 237 

Water  accumulators,  description  and  dimensions 

of 267 

typical  connections  to  conserving  valve ....  173 
typical    connections    to    pressure-reducing 

valve 267 

-control  tank,  description  of 264 

dimensions  of 266 

selection  of  size  of 138,  142 

-seal  motors,  attachments  for 294 

-seal  traps,  attachments  for 295 


367 


WARREN  WERSTER  &  COMPANY 

EXECUTIVE  OFFICES  AND  WORKS 
GAMDEN,  N.  J. 


BRANCH  OFFICES  AND  REPRESENTATIVES 


Atlanta,  Ga. 
Atlantic  City,  N.  J. 
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Birmingham,  Ala. 
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Chicago,  111. 
Cincinnati,  Ohio 
Cleveland,  Ohio 
Columbus,  Ohio 
Dallas,  Texas 
Denver,  Colo. 


Detroit,  Mich. 
Easton,  Pa. 
Grand  Rapids,  Mich. 
Houston,  Texas 
Indianapolis,  Ind. 
Kansas  City,  Mo. 
Los  Angeles,  Cal. 
Memphis,  Tenn. 
Milwaukee,  Wis. 
Minneapolis,  Minn. 
New  Orleans,  La. 
New  York,  N.  Y. 
Omaha,  Neb. 


Philadelphia,  Pa. 
Pittsburgh,  Pa. 
Portland,  Ore. 
Rochester,  N.  Y. 
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San  Francisco,  Cal. 
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Washington,  D.  C. 
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SOLE  REPRESENTATIVES  AND  MANUFACTURERS  IN  CANADA 

DARLING   BROTHERS,  LIMITED 

Head  Office  and  Works,  Montreal,  P.  Q. 

BRANCH  OFFICES  AND  REPRESENTATIVES 

Calgary  Ottawa  Quebec  Vancouver 

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London,  England 
THE  ATMOSPHERIC  STEAM  HEATING  CO.,  LTD. 


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